Q1: For Quick Car 50-864 Ignition Switch Panel, shouldn't I hook this up to wires at the ignition barrel rather than going direct to the starter motor as to retain clutch switch? The instructions on this panel are....lacking.

Q2: I do not yet have a battery disconnect (coming soon), so for now I imagine I can shut the car off using the ignition switch once this is installed?

Some background: I'm in the process of converting car to dedicated track car. I'm currently at the part where I have removed the center trim and needed to relocate the fuel door and traction control buttons. This part is complete and tested successfully. Thanks to this awesome forum, I knew that only wires needed were 5 and 6 off the harness hooked to a momentary switch. So I replaced two of the switches with momentary switches and got fuel door and traction control working. See pics below for progress.

 

The car has four power circuits at the ignition switch; Start-Yellow wire, Ignition Start-Pink wire, Ignition Run-Orange wire and Accessories-Brown wire. The two large red wires are fused with 60 amp fuses directly from the battery as seen in the in-car footwell fuse box. If you want to use the new panel shown above instead of the ignition switch just remove the ignitioin switch and put insulated spade connectors to the above described wire pins in the black and white connectors. If you want to revert back to the ignition switch the wires can be unplugged and the switch put back to it's original location. To start the car the new switches would control the ignition start and the start button would operate as normal using the safety interlocks as before. Once the car is started the other circuits can be turned on such as ignition run. To turn off the car the new ignition switches would do that. There is another switch you might need to add to tell the car if the key is in or out assuming you don't use a key in the future. The small black wire goes to a SPDT toggle switch common, the small tan wire goes to the same switch normally closed (key out) and the small green/black wire goes to the same switch normally open (key in). All three are in the same white and black connectors that were unplugged from the ignitioin switch. A resistor with the same value as the one in the key can be attached to the two small loose wires that surrounded the ignition switch to defeat the security of not using a key.

 

My answers here are part opinion, and mostly experience from building and maintaining many race cars and "restomod" street cars or just modified street cars over the years. You may get differing opinions and differing experiences. That's what the Internet is about.

It sounds like you have a (mostly) intact factory wiring harness for your car. When I have that, I generally pull the "plug" (female or mostly female) from the back of the factory ignition switch. If a male side of the connector housing is available, I used that for a pigtail harness that I wire to the panel. Otherwise, I use my connector tools to pull the female spade receptacles out of the nylon/plastic connector frame, and I find one or two appropriate latching connector frame sets from my extensive collection (or from Amazon or other online sources) and I push the metal connector terminals into a new connector frame. I then wire the male side of the connector to the panel.

If I'm dealing with a factory built production "street car" which has had every factory wire removed from the car and discarded, I get a wiring kit from someplace like American Auto Wire, and I use their wiring. Again, I'll probably put their wire terminals for the ignition switch into a connector frame that I have (or can get) a mate for to make the final wiring at the panel.

One note, I think your C5 was equipped by the factory with an "imobilizer" system. You'll have to "tune that out" as part of your PCM tuning, and you should carefully remove the hardware and associated wiring for that from your wiring harness.

A few more things. The red "Ignition" circuit on that panel should provide power to the switched ignition power wire(s) on the PCM, the power for the fuel injectors and for the coil packs. On GM vehicles generally (this should apply to the C5), those are the pink wires (or striped pink).

There is/are some wires from the ignition switch which are on in the "accessory" and "run" positions which get turned off in the "start" position. Use the green switches at the end furthest from the start button for those circuits.

If you use electric gauges, put those on the green switch next to the red "ignition" switch. One or two switches there should turn on everything needed for "normal" operation of the car.

Never use one of those switches as a manual fuel pump switch. Keep the PCM controlled fuel pump relay system and test that system whenever you make any big changes to the wiring (like after you install this panel). If you have a fuel pressure tester with a bleed valve, install that at the fuel rail, start the engine, then push the clutch pedal and select 4th gear, then release the clutch to stall the engine. Get out and bleed the pressure from the fuel system. If you get more than a half cup or so of fuel from bleeding the system, fix it. If the fuel pump is still running, fix that before you drive the car anywhere. I know two people whose lives were changed forever when they were in accidents and the electric fuel pump did not shut off. One was a race car where the fuel pump was powered by a switch on a panel like that, and he was knocked out in the impact and never shut it off. The other guy was driving a street car that "Bubba" had "fixed" so the fuel pump ran when the key was on, rather than locating the actual problem and repairing the safety system. They both spent more than 6 months in the hospital recovering from severe burns. Don't be like either of those guys.

Also, the starting procedure varies with your engine budget.

If you have a NASCAR team (Cup, Xfinity or Truck) behind you with a good supply of race engines, or a similar unlimited budget, do it like you see on TV, just run across the panel flipping all the switches on and press the start button. Don't worry about things like engine bearings, that's the team's responsibility and they're going to change out engines before next week's race anyway.

If you want your engine to last as long as possible, then follow this procedure instead:

1. Turn on the red ignition switch. This will let the fuel pump prime while you do the next step.
2. Turn on the green switch(es) next to the red switch to turn on the panel gauges and any other circuits which need power to start and run the engine.
3. Turn off the red ignition switch. <<<VERY IMPORTANT!!!
4. Place your index finger knuckle under the red switch and use your thumb to push the starter button. Watch the oil pressure gauge. When you have oil pressure showing on the gauge, then flip the red ignition switch on and release the starter button when the engine fires.
5. Finally, if any of the green switches on the far end are necessary at this time, turn those on after then engine is running.

Oh, and about that clutch safety switch. Unless the rules you run under prohibit it, I generally remove/disable the clutch/neutral safety function. There have been times I've been on the track, in an unsafe location, with an engine that won't start or run. It's really handy to put the thing in 2nd gear (or reverse) and push the starter button to move the car to a safe(r) position. If the safety devices are required to work by your organizers, I'd still stash an override switch somewhere, to allow it to be overriden by the driver.
Be sure to get a battery disconnect switch/device that is designed for a car with an alternator. It's very important that the alternator be loaded when the battery is disconnected. If you just cut out the battery, that can cause a high voltage spike that can fry electronics (like a PCM), or trip any "overvoltage protection" systems on the car (common on German cars, I don't know if the C5 has anything like that). Don't ask me how I know these things.

 

So it sounds like I have a few options here:

1) Run the QuickCar included wires to the starter through the passenger footwell, get some resistors for the key lockout, then hook ignition wire from cylinder to ignition switch, run ACC wire to next switch.

OR

2) Same as above but run everything directly to the ignition cylinder rather than going to starter motor.

Sounds about right? Trying to decide which would be easier. Both have their advantages....

 

Sounds about right. I had some spare time to doodle on my draw program this morning, and to look up some more info on this.

Hypothetically, if you were to call me and ask me to come install this for you, here's what I'd bring and what I'd do. It's pretty much your #2 choice, with a few key differences (pun intended).

How I'd prepare: I'd make a few calls and internet searches for matching male connectors for the two "6 position mixed" connectors at the ignition switch. If the matching male connectors for that are available, that would change things just slightly. My doodle drawings and my plan is based on those not being available.


What I'd bring:

• Some 6 pin connectors. You can get these on amazon: https://amzn.com/B07Z54M7RD
  (If matching male connectors for the ignition switch female mixed connectors are available, I'd bring those instead)
• Male terminals (0.25"/6.3mm, with locking tang) for 10-12AWG wire for those connectors. I got some on Amazon a while back, but those are no longer available. I generally get them locally. (note: the brass terminals included with the connectors are for 14-16AWG wires and will not work properly for the larger wires you'll be dealing with).
• Wire all copper, all stranded, Red, 10AWG and/or 12AWG (I'd bring both, more on this below), Pink 12AWG, Orange 12AWG, Brown 12AWG, Yellow 12AWG or 14AWG.
• Assorted terminal extractor tools, crimpers, wire cutters and wire strippers. Note: you can probably use a small "jeweler's" screwdriver to extract the terminals from the connectors on this particular project.

The plan:

DISCONNECT THE BATTERY BEFORE YOU START THIS PROJECT!!!!

For the female connector:

1. Unplug the white(ish) and black connectors from the ignition switch. If you've sourced matching male connectors, you're done at this point. Skip to the "for the male connector and switch panel" section.
2. I'd extract the female terminals from the existing white(ish) female connector. You want the terminals (and wires) for the Red wire, the yellow wire and the orange wire.
3. Reset (bend out so they will catch) the locking tangs on those three terminals and push those terminals into the 6 position connector across the "top" (the side with the latch/catch). See the drawing here:
   
   
   Female connector, looking at face of the connector, wires are behind connector. Top wires are from white(ish) ignition switch connector, bottom wires are from black ignition switch connector.
   
4. Unplug the black connector from the ignition switch. Extract the female terminals for the red, pink and brown wires.
5. Reset the locking tangs on the terminals and insert the red, pink and brown wire terminals into the bottom half of the 6 pin connector.

For the male connector wired to the panel:

1. Crimp male terminal pins on the orange, yellow, pink, and black wires. Terminate the yellow wire as appropriate for the push button. Terminate the other three wires as appropriate for the first three switches in the panel. Connect the switches and push the connector terminals into the male 6 pin connector frame according to this drawing:
   
   
   Wiring from the male connector to the switch panel. Looking at this from the back of the connector where the wires are sticking out.
   NOTE: if you source the actual male mates to the female connectors the factory used, you'd use the mate to the white(ish) connect for the top three wires, and the mate to the black connector for the bottom three wires.
2. For the red wires, I think you'll find the harness wires are 10AWG, not 12AWG. If that's the case, there are several ways to go. If it's trivial to attach two heavy gauge wires to the "Ign" and "Main" switches, I'd run 10AWG wire from the connector to those switches, then use a 12AWG jumper wire from the "Ign" switch to the "Accy" switch, and another 12AWG jumper wire from the "Main" switch to the "Start" push button switch. If two heavy gauge wires won't attach easily to a single switch, I'd either crimp 2 wires, both 12AWG into the terminal for the connector and run both wires to their respective switches, or I'd crimp a 10AWG wire into the terminal for the connector and do a soldered splice wrapped in heat shrink tubing to two 12AWG wires to run to the switches.

In case the viewing angle isn't clear from the pics, the wires connect so that each color goes through the connector to the same color. The way I drew the pix, you're looking into the face of the female connector, and at the wires sticking out the back of the male connector.

Once you have that done, you've got your panel wired and easily connected with the latching 6 pin connector.

About that key and the small connector with the purple/white and white/black wires, I'd recommend getting rid of it entirely and having whoever does your dyno-tune just tune it out. Until that happens, I'd put a key in the lock cylinder, wrap that whole assembly in racers tape (AKA duct tape) and tape or zip tie it to the structure in the dash. Leave the wires plugged in. When you take the car to the tuner for a dyno tune, unplug the wires, cut the lock cylinder/key loose and carry that to the guy writing up the work order for the tune. Hand the key/lock cylinder to the guy and tell him the tech might need that to start the car and pull it into the bay, but when you pick it up, you want them to hand you the key and lock just like it is (unplugged), and you don't want anything plugged into that connector and the engine needs to run so you can drive it. It's trivial to "tune out" the security for the key, and I wouldn't want the key or any extra resistors and plugs in my race car. That's a feature I would definitely want completely removed in the tuning step.

A couple of other notes. I don't have a C5 here, and I don't have access to factory service information at the moment either. I got the information for this from the internet. A special thanks to @byronhunter here for his post https://www.corvetteforum.com/forums...post1573207940 with the best information about connector colors and wire colors.

 

This is super helpful, thank you! I ordered a battery disconnect (with alternator posts) since I was already going to be altering the ignition circuit, pretty sure I can sort out how to fit that into your instructions!

Again, thanks for the help, this is very informative!

 

You can tune the security out of the PCM but not the BCM. Without the VATS key connected, the BCM will not energize the starter relay meaning the starter will not engage. If you're keeping the BCM, the easiest way to solve this is to replace the key and cylinder with a resistor of the correct value properly soldered and heat shrink'ed to the VATS wires.

 

OK. I'll ask, even if @theox05 won't.

For a track only race car, what are the reasons you'd want to keep the BCM? What do you lose by removing the BCM? Finally, what's involved in completely removing the BCM (and associated wiring)?

I'll confess that in my most recent LSx project (LS1 transplanted into mid 1970's Datsun Z car), we ran the yellow wire (it was purple for us) from the start button to the starter solenoid. But we were using a third party "standalone LS1" wiring harness for the engine, and another third party "restomod" wiring harness for the rest of the body wiring (lights, gauges, HVAC, wipers, etc.), not the GM harnesses from the LS1 powered donor vehicle. We had no BCM on that car. I have more experience with this type of wiring than with BCM equipped LSx powered cars, especially recently.

 

I would guess that it depends on what functions you want to keep in the car, which would depend on how far into a race car you are turning it. There is lots of stuff that will just simply keep working if you leave the BCM, like the neutral safety switch, trunk release and interior lights as examples.

 

So I'm a novice at this stuff, first ignition I've tried to wire. Can you tell me the start procedure and the difference between main and ignition circuits?

Also, with the battery disconnect, its the one with a spot for the alternator. The battery/alternator side of the switch makes total sense. Go to battery and go to alternator output wire. However the other two posts (starter and electrical panel) are a bit of a mystery to me. I THINK it means Yellow wire to the battery disconnect for starter THEN goto panel as drawn. For electrical panel the red (hot) wire that runs to the main/acc switches goes to cutoff switch first and then to my switch panel as drawn?

 

One more question, I bought the package you suggested, but where should I look to acquire the male connections for 10-12 gauge wire? I think this is it:

However, is there a good local source for these things? Like HD or Lowes, maybe an electrical supply store? We have a MicroCenter in Denver, maybe there?

Thanks!

 

The Baomain terminals you linked are the same 14-16AWG terminals that come with the connector sets. Too small for (most of) the wires you're dealing with.

For the male terminals for your panel connections, check https://ceautoelectricsupply.com/pro...ale-terminals/ That site sells the terminals for all different wire sizes from 10AWG down to 18-20AWG.

My local source was the local CarQuest franchisee (now a Napa franchisee after merging with the local Napa franchisee soon after Advance bought out CarQuest). I haven't seen these terminals in there in the past year or two (the merger/change came about 5 years ago). A more "professional" parts store, aimed at supplying service shops might be able to get them.

If you don't have a good crimping tool, get one. There are ratcheting ones, but I find the non-ratcheting type give me better results even though I have to do two separate crimps on those terminals (one on the wire conductor, a second crimp on the insulation). I love my SK tools 7801, and it's wired many harnesses and connectors on many vehicles. If you're on a budget, the Iwiss one on Amazon isn't bad. https://amzn.com/B071KFLY43

About the battery cutoff switch, I'll come back later this evening or in the morning with much more detailed help there. It would be helpful to know a few things.

* Exactly what battery cutoff switch do you have. Manufacture, part number, and if there's a UPC code on the packaging, the full 12 digit UPC code (including the tiny leading digit in the lower left and the small trailing check digit on the lower right).
* Where do you think you're going to locate the switch. I'll actually make a very strong recommendation that you locate it on the passenger side of the firewall below the windshield (notch the back of the hood to clear it) or possibly at the back of the right front fender, by the base of the A pillar (I'm not sure if there's enough room for it there).

Short description now:

There are two large posts (5/16" or 3/8" or M8 or M10 if it's metric), often copper, that are for the battery cutoff itself. It installs like a solenoid on a Ford (or any vehicle where the solenoid is separate from the starter. You have a battery cable going from the positive battery post to the switch, and a "solenoid to starter" type cable (battery cable size wire, but ring lugs on both ends) that goes from the switch to the starter. You're replacing the battery cable assembly with two cables with the switch in the circuit. Any smaller wires that are part of your current battery cable assembly (going to fuse blocks or whatever) get cut, stripped and have ring lugs to fit the posts on the switch, and you put those on the post with the wire going to the starter. You want every circuit to be shut off when you turn off the battery cutoff.

The alternator cutoff is a little more complex, and it can vary a little depending on exactly which switch you have. That's why I need manufacturer, part number and UPC code if there is one.

 

Awesome, thank you!

I bought this: https://www.summitracing.com/parts/m...CABEgLFIfD_BwE

UPC: 084663741081

Still trying to source those connectors, I took the week off so I'll start searching stores in earnest tomorrow.

 

No dice in any of the 7 stores I went to, so went ahead and ordered them from the site you referenced.

 

Yeah, I've got to order some soon myself. I almost PMed you to offer to send you some for shipping plus a small amount, but I checked my electrical parts organizer bin first, and I only have 2 of those terminals right now.

Well, first of all, I'll say that if you absolutely, positively have to install a cutoff switch, that's a good one.

Do the rules where you race absolutely require a switch? What type of racing are you planning to do? Is the rule book online?

You won't want to hear this, but your car will be safer with the stock battery/starter/charging system wiring, in the stock location, with all of the stock wiring tiedowns, standoffs, clamps, etc. If you install that switch, you'll be making the car (and the electrical system) less safe overall. If you make other mods (remove the stock exhaust manifolds and install headers as one example) that change the environment in the immediate area of the stock unfused wires and cables, you might need to add a bit of insulation or other protection, but hear me out on this. Also, confirm what the unfused cables in the battery/starter/alternator circuits look like on the C5, because I think I remember, but it's possibly faulty memory here.

First, the wires involved in this project are this battery cable assembly:


The heavy wire (4AWG?) goes to the starter. The smaller wire (8AWG? Maybe 6AWG?) goes to the "fuse/relay center" panel under the hood, in front of the battery IIRC.

You also have a charge wire (6AWG) going from the alternator to the big post on the starter solenoid (where the battery cable attaches) that looks like this one:


On some of the factory wires, I think that last one might have had a fusible link soldered/shrink wrapped in on the end that attaches to the starter.

The reason I say this is safe (enough) if the factory cables are held in place by all of the factory tie downs, clamps and hardware is because GM safety engineers had decades of crash test data, and they even crashed several C5s every year they were produced. One of the things they examine in the wreckage after the crash tests is all of the "unfused power cables/wires." including the ones you'll be removing and replacing with your own design for the cutoff switch. If those cables are damage in any of the crash tests, GM will likely alter the design of the cables and the routing and the tie downs and other locating hardware so that no damage will occur in the crash tests. C5's aren't know for electrical fires and exploding batteries in minor fender benders, or even in more serious accidents where the battery wasn't directly involved in the collision. Installing a cutoff switch and altering the routing and support of those two cable assemblies (the three wires in them) isn't likely to make the system any safer. If done without a lot of thought and care, it's far more likely to make things less safe. Since you're unlikely to conduct your own crash testing on multiple C5's with your cutoff switch installation, you won't know how your setup will do in an actual crash until you have an unintentional "field test" on yours.

I'll address a few things about selecting the location and physically installing the switch first. Actually, first, let's establish what the switch is for, and who uses it, because that's important. The switch is for track emergency workers to turn off all of the electrical circuits in your car and to stop the engine if it's still running. They need to do this quickly and easily after you've crashed so bad you're unable to turn things off yourself! That's the primary purpose and function of the cutoff switch. It needs to be on the outside of the car, or easily accessed from outside the car.

Unless you've been driving around in your race car, making laps or making runs down the drag strip, and you've thought, "What I really need in this car is an energized arc welder electrode, within handy reach, maybe right next to my leg," you don't want the master cutoff switch in the cockpit or anywhere near your body.

For a C5, I'd mount the thing on a bracket at the top of the firewall and notch the back edge of the hood for clearance so you can close the hood and the switch is visible and accessible. I'd probably have it closer to the battery (offset to the right side of the car). Be careful that your hood won't slide to the rear in a frontal impact and take off the switch handle or bend the switch shaft making it impossible to turn. That's a bigger problem for the switches with the red plastic "key".

You also want the switch connections to be as close as possible to the stock routing of the battery to starter cable. You'll be replacing that with two cables, one from the switch to the starter and one from the switch to the battery. The one to the battery should go directly to the battery, be as short as possible, and should not pass through any bulkhead or metal panel. If the factory cable goes through a bulkhead, we'll discuss that for the cable from the switch to the starter. That's the cable you want to pass through any bulkhead or panel. The battery to switch cable remains energized, even if the switch is turned off. It's still a hazard if the conductor in it touches grounded metal.

Oh, and all the posts on the switch should have rubber boots covering the exposed posts. Amazon has these: https://amzn.com/B017E0869A and Summit Racing has these: https://www.summitracing.com/parts/aaf-all76152 Whichever you prefer (there are other alternatives on both sites), you'll need 4 of those boots.

I also strongly prefer to wrap all unfused power cables/wires under the hood in red corrugated plastic "split loom." You'll probably need some in several sizes. 1/4" or 3/8" for the wire to the fuse block (1/4" for 8AWG, 3/8" for 6AWG), 3/8" for the charge wire from the general vicinity of the starter to the alternator, and a small amount for the end of that cable by the switch. 1/2" or 3/4" for the short cable from the battery to the switch, and probably 1" (maybe 3/4") for the alternator and starter wires together running from the switch to the starter. Amazon and Summit both have that stuff. If you can't find it, let me know.

You also may need some thermal insulating sleeves for the starter wire and the alternator charge wire.

Oh, and if I was installing this, I'd use one fusible link wire in the connection to the alternator at the switch end. From Amazon, https://amzn.com/B0040D0QY8 or GM Part # 12077140 or something that cross references to that. That's 10AWG (or 5.0 sq. mm).

If I haven't talked you out of this, I'll try to make a wiring diagram this evening or in the morning. It's pretty simple, but I'd strongly recommend doing it a little different than the "instruction sheet" that Moroso includes with that switch. For one thing, it's always made more sense to me to hook the Battery to the "B" side and the Alternator to the "A" side. I think the instructions tell you to do it the other way. Both switch contacts are identical, rated for the same 125A continuous, 750A peak current, so either way works, but you can probably see why I do it "backwards" from the instructions.

 

Thanks for all the info! Yea, I gotta have it apparently, looking to race in NASA events. Here is the relevant section of the CCR:

It looks like installing the battery cutoff does not affect my ignition work? As in, if I go ahead and do the work on hooking the ignition panel up I won't have to go back and rewire anything around there when I do the battery cutoff. I just need to do the wiring with battery/alternator/starter/fusebox. Was kind of thrown since the panel instructions talked about hooking up to battery disconnect.

Also, will take your advice and get the cutoff installed outside the cockpit. Thank you again!

 

The instructions for the panel probably assume you're building the entire wiring harness, not modifying an existing harness. You'll be able to use the two red wires from the ignition switch as your "to the battery disconnect" wires.

And yes, you can finish the switch panel for the ignition switch functions without installing the master cutoff switch. They are completely separate for your setup.

Are you installing anything on the "except..." list? Fire system that needs vehicle 12V power? Radio powered by the vehicle 12V power that you want to work with the master cutoff turned off?

About the master cutoff. Don't install it in the fender panel. You never want it to be in a location where the there's only a thin bodywork panel between the switch and "race traffic" (competitors, especially any who might be angry with you). If you get some "rubbing is racing" on the panel with the switch in it, your car can coast to a stop and your battery can explode if someone hits that panel just wrong (or just right from their perspective). I've been on the "learning" side of that lesson twice (once in a car that I didn't own and didn't prepare, and I warned the car owner about that problem before I even started the thing the first time that weekend), and on the "teaching" side once that I'll admit to.

I'm full of questions. A few more about the charging system.

Also, can you look at (or take a pic of) the small connector on the alternator. I believe it's a four position "weatherpack" connector with only one or two wires in the thing (two or three unused positions)? I'm curious about wire colors there. You could also try a test once you have the switch panel finished. Put a volt meter across the battery, measure voltage with the engine running, and see if it drops from 14.xV to 12.xV at the battery when you unplug that small connector plugged into the alternator (not the big wire on the screw post, leave that connected). Your dash display will freak out with "Charging system" problems when you disconnect it, but there will be no permanent damage.

 

One more question. Will you be getting this thing "tuned"? Loading custom maps and settings into the PCM?

 

I'll get a pic of the alternator once its back from the alignment shop. For tuning, no, I have no plans to tune. 405 HP is plenty for me at the moment, I'm limited by my own skill rather than HP. Still have a lot to learn.

 

OK. Here's my wiring diagram for the cutoff switch if you intend to use it "as designed." Depending on your alternator, this may be the best configuration for you. That depends on how many wires are populated in the small 4 pin connector at the alternator. If there's only one wire there, this is your only choice.

Here's the diagram (not even close to scale):


Wiring for Moroso master cutoff switch, installed as designed.
A few notes about this.

The battery cable and the switch to alternator cable should be the same size as your existing battery to starter cable. I'm pretty sure it's 4 gauge (4AWG) on the C5.

The cable from the switch to the alternator "B" post (sometimes marked "BAT") should be the same size as the stock cable. I'm pretty sure it's 6AWG on the C5. Since the factory cable is routed to the starter, I'd probably route your replacement the same way, through all the factory tie downs, stand offs and clamps. Once you get near the starter, I'd bundle it the same corrugated plastic split conduit/loom with the wire from the starter to the switch, and rout them together. You might need some additional tie downs or stand offs along that length of conduit to hold it in place and route it to the switch.

I used a blue line for the fusible link wire in the diagram. They come in many colors, depending on the source. The color doesn't matter, the size matters. It should be 10 gauge (10AWG, or 5.0 sq. mm if it's metric). The fusible link is like a very high current "slow blow" fuse. The purpose of that fusible link is to isolate the alternator if for some reason the big (6 gauge) alternator charge wire shorts to ground. If that happens, the fusible link will burn out and you might be able to continue. The most likely scenario in that case is that the diodes in the alternator will also burn out. Whether that causes an electrical fire depends on your speed, airflow around the alternator, and your luck. I've seen a few cases where this happened and the car ran to the end of the race, or until the battery discharged completely. I've also seen electrical fires and other bad outcomes.

Make sure the cable from the switch to the battery is insulated and protected. If that one shorts to ground, your battery will spew it's juice, and you might have an electrical fire.

The battery cable and the switch to starter cables should be available at any decent auto parts store. The one from the switch to the starter might be sold as "solenoid to starter," but you should be able to find one the correct length.

The alternator charge cable will probably have to be custom made. A really good auto parts place might have the tools to do that, or an RV shop can do it for you. They use that size cable in various custom lengths for "inverter to battery" cable sets. To do the crimping for the rings on 6AWG wire, you really need a good crimping tool. When I'm dealing with that size or larger, I go to my parts store and they've got a 20ton hydraulic crimper with dies for 8AWG up to 4/0AWG. Those aren't "do it yourself" crimps. Ask your shop what tools they will use before you let them do this job. There are some "hammer operated" crimpers that don't make as secure a crimp. I wouldn't take it to someone who will use that type of crimper.

I also generally cut the wire, slip the crimp terminals on and test fit everything. When I'm sure I've got it right, I tin the wire with a little bit of solder (a thin coating, not a big blob), and tin the inside of the crimp terminal with a thin solder layer. Then I take it in for the crimping operation. They charge me $5 to $10 depending on who it is and their mood to crimp both ends of a cable. If it's busy and the owner is there, he'll sometimes just take me back to the crimper and tell me he doesn't have time, I can do it myself. After crimping, I heat the thing back up and flow some more solder into the crimped joint to finish the soldering. Then I put heat shrink tubing over the thing and shrink that down to insulate everything but the ring itself.

The wire from the switch to the fuse block will be stock size (either 8AWG or 6AWG on your C5), and may have to be custom made as well. I'll crimp my own 8AWG rings, but 6AWG goes to the big hydraulic crimper at my parts place.

The fusible link is 10AWG, and you should be able to crimp rings on that yourself. I linked to the tool somewhere up in the stuff I posted about the switch panel. You can use one of the bigger jaws designed for the insulation to crimp a 10AWG ring terminal. It works, and it will make a good crimp.

Finally, I generally add a boot on the starter post and the fuse block post if there isn't a boot on the stock wire.

Use red wire everywhere, and I prefer red corrugated split conduits and red boots. On my race prepped cars, red means "unfused power, beware." Just like yellow on street vehicles means "air bag related circuits."

I'm sure I'm forgetting something else. But this should get you started.