My 7 and 8 plugs are really easy to get to but I have no evap box installed. My engine is also set in place with k-member extensions, C5 mount pedestals and big block mopar mounts. I don't think the engine is in the exact same place as other swappers that use the ls swap plates. Even when I had the evap box installed the 8 plug wasn't that bad. I could put the ratchet/socket and break it loose and then use a rubber hose to screw it out and back in. 8 plug took about 10-15 minutes. Now I can do all of them in about 15 minutes.

I don't know for sure about your headers/manifolds. I bought my swap car complete. It certainly looks like I could get them out and back in with the engine in place if needed but I don't know for sure.

 

Spark plug changes aren't too bad on my LS. Driver's side rear plug can be accessed from the top (same as the L98) Its hard to access the passenger's side rear plug from the top, but you can very easily access it by jacking the car up and reaching up from underneath the car.

 

Thanks for the response guys.
Short update time.
This weekend's plan almost got thrown out because of some goofs from the company I purchased my pistons from, they sent 1mm oversize pistons instead of the standard bore I wanted, but I was able to get another set on order from a different supplier and those should be delivered tomorrow. (PS if anyone is looking for some gen 4 silvolite flat-top high compression coated pistons for 1mm overbore in a 5.3, let me know, I may know a guy )
Here's what to expect from this coming weekend:
The plan is Saturday will be a short day with the final assembly of the LS and engine pull out of the C4, it'll also be the day where I decide if I am rebuilding the vehicle side harness. I may not have mentioned it yet, but this car had some crazy electrical gremlins that I have given up chasing down with the L98, I grew tired of throwing money and parts at it, but that's what I get for buying a decade abandoned C4. I have a couple of friends coming over to help remove the hood, unfortunately there just isn't enough room within the storage unit to pull the engine from the side, so it'll have to be plucked from the front.
Sunday is the REAL Funday, there are two big things I want to accomplish, LS harness integration, and having the LS sitting in the frame by sundown. When I say LS harness integration, I really mean finding what parts of the vehicle harness are still in good enough shape to be able to still use, and what parts I need to cut and integrate into the LS harness. For example, the fuel pump, and fan circuit work great with no issues so I'll be breaking out the LS harness wires out from the harness and routing them to the respective relays for those functions, and bypassing the LS fuse block. The PCM power, diagnostic port, and other stuff like that, I'll be leaving until I'm closer to starting the Vette after the transplant. Oh, I may end up making an LS swap electrical guide if there's interest, I've been studying the LS harness and my FSM and put together a high level roadmap of what works and what doesn't between the two.
Some other stuff that may be happening, some of you may have seen my other thread about using the C5 batwing oil pan and the conclusion is that with that pan you cannot run long tube headers with said pan, I decided to order some eBay C5 long tube headers, and keep my shorties to the side in case they don't work. Looking at pictures,(the car being 20 miles away makes this a leap of faith) it looks like there may just barely be enough room to fit the whole setup in with some massaging and a BFH. I'm really hopeful that it'll work because that means I'll be able to run it with the headers dumped and take it for its first test drive sooner rather than later, maybe even drive it the 20 miles home and get to tune some. This is my second to last weekend with the storage unit, so I have less than 96 hours to get this swap roadworthy, place your bets, ladies and gentlemen.

 

Awesome another LS swapper. I see that you have an older gen 3 LS block (I prefer them over the DOD crap/58 tooth/front cover cam sensor). I just built an 5.3 L33 aluminum block engine with my son. The cam bearing didn't have any babbitt left on the bearing shell.

Curious on which rods you going with? Piston and head combo? We used 4.8 flat top pistons, gen 4 rods with ARP rod bolts, should be good for 7000 rpm. Sloppy stage 2 cam 585lift and 228/230 at 50. 799 heads, just some simple clean-up and pac springs.

 

Gen 4 rods, with stock bolts, the rods will fail before the bolts do, so I couldn't justify the cost of ARPs. My setup is identical to yours minus 799 heads, I'm sticking to the 862s for now until I find 799s or 243s, the higher compression with the 862 will also make it feel just barely more sportier, but it does mean expensive gas. At the power levels I'm at and NA, the flow differences won't make more than a few HP difference.with that said, I specifically went for an L59 so I had the base items I needed to run it flex, a 50%50% mix keeps me more than safe and will hopefully keep my wallet from feeling the burn... atleast for the break in period. After break in, I'll be switching back to my own ECM and that's when the fun begins.
Update so far, motors pulled, wiper motor cover in also in pieces, I'm gonna try and 3D print a replacement, but from what ive read, the motor doesn't fit anyway. I've put the motor build on pause, the cam bearings are in with Loctite Bearing Retainer (not nearly as difficult as it seemed, cam went right in), but I'm not comfortable with the general cleanliness of the block after honing. Both motors will be coming home with me sometime during the week, and the LS will be getting a thorough pressure wash. I spent all day working on the heads, general cleanup and quick valve lap to get rid of some discoloration and check seat health. I'm currently working on removing three broken exhaust bolts, two of them are easy, the last is recessed so I need to get some copper tube the right size so I can get it out



Victory!

 

Today's Update:
LS Short block is all put together, took me 3 different sets of snap ring pliers to be able to get the snap rings that retain the wrist pins on. So far, I'm really happy with the build, break-away torque for the crank was coming in at 25-27 lb/ft and 17-20 to keep it going, its better than I was expecting, gives me some hope that this thing may not need all that long of a break-in. I ran into an issue with the rod-bolts, using my electronic torque wrench I was not getting consistent results on the max torque from rod to rod after torquing to 85* and I'm not comfortable with that at all, variance was almost 10lb/ft across the motor so I'm gonna pop the bolts out and spritz them with brake cleaner to dry them and hopefully get more consistent results. I'm not sure how to verify if the bolts are too far gone just yet, for some reason I tried to push through it and torque the bolts to match, and ended up with bolts that can't quite reach spec. I can't find any bolts locally which means putting completing the engine build off for another week; my lease on the unit is up the 5th so times a-ticking, I hate making decisions like this.
Electrically, I worked on the LS harness last night, removed the DBC, auto trans, and rear O2 provisions from the harness, and will be test fitting it tomorrow to see where and what I need to extend before it goes into woven loom and not the crappy corrugated stuff. Since I already modded the harness to work with a standalone, the LS harness integration should be pretty straightforward, here's to hoping.

I'm getting an early start tomorrow, after the rod bolt dilemma is solved all that left is valve spring and seal replacement, a quick valve lap and pattern check, and lastly the trunnion upgrade, I may put off the last one since it is something I can do on the driveway back home. A real progress update with pictures will be coming tomorrow, for now, I'm gonna get some sleep so I can work sunrise to sunset tomorrow.

 

Who knew lapping valves could be such a pain? Valves were not passing the alcohol leak test so had to keep going, none of the valves look sunk so I think I'm still in the clear. Took me a good bit longer than I wanted, note to anyone lapping valves in the future, don't use an old tube of compound, it is not worth the few dollars of savings.
The final countdown has begun, the last few parts have begun trickling in, my fuel system parts finally arrived today and the long block has been fully assembled. The heads are on, and I gave the motor a few spins with the compression gauge in for giggles and got a whopping 90PSI turning it over by hand with my 1-foot breaker bar. It takes a good 80lbft to get it past the compression stroke, good results for just spinning it over by hand considering GM minimum spec is 105PSI at cranking speed.
The rest of this build will hopefully occur within the next 60 to 70 hours, and I'll either get to drive an LS swapped C4 home on Monday or have to tow it from the storage unit.

Schedule for the weekend's events:
Saturday:
Fuel System, Engine Mockup/Install, C-Beam Mods, Hydro ToB setup, and "Exhaust" test fit
Sunday:
Electrical, Engine Ancillaries, and First Fire
Monday:
Car Reassembly, Cutting the Hood, Base Tune, and Driving/Towing Home
It's gonna be a looooonnng weekend, I will either update the thread after I get home each day or have one long post on Tuesday. Tomorrow is looking like it's gonna be an all-nighter...
A Few Specifics:
Engine Build Recap:

• Silvolite Coated Flat Top Pistons: Brings compression to 10.39:1 if my math is correct.
• Mahle Moly Faced Rings
• PAC-1218 Valve Springs
• Refreshed 862 Heads (All valve seals replaced with high temp exhaust seals)
• Gen 4 Rods + ARP Rod Bolts (didn't feel confident in the stock rod bolts, bolts did not consistently torque dry or wet during torque to angle)
• Elgin Sloppy Stage 2, joining the bandwagon with this one
• Comp Cams Trunnion Upgrade
• C5 One-Piece Oil Pan
• Billet Barbell
• HV Oil Pump, Stock Relief Spring
• Oil Pickup Brace
• Truck Manifold
• 33lb Flex Injectors

It's your basic run-of-the-mill 5.3 build, I'm looking for 243 or 799 heads to compliment the flat tops. All in all, it'll be a nice rev-happy rig that will still be fun to drive around town, estimated to put down 375+ to the wheels, and should match the L98 torque wise or come close to it.

Fuel System:

• Fuel Rail
  • OE Stainless, Returnless
• Regulator
  • Aeromotive 13109
• Fuel Lines
  • OE lines until fuel filter, -6 PTFE lines to regulator and rails
  • All lines will be converted to -6 in near future
  • Required Adapters:
    • Return Side: 14MM X 1.5
      Return Side: 14MM X 1.5
      x1 84-87, not used 87+
    • Feed Side: 16MM X 1.5 x1 84-87 x2 87+
    • Fuel Rail and Flex Sensor: Quick Disconnect x3
  • Sensors
    • Flex Sensor, ACDelco
      Flex Sensor, ACDelco

Engine Mounts:

• ICT Billet Swap Mounts, Will Confirm Position
  ICT Billet Swap Mounts, Will Confirm Position
  • Looks like 2nd position from the front and slotted C-beam are the best options for the least clearance issues.

Exhaust:

• Chinese C5 Corvette Long Tubes(Cheaper on Ebay)
  Chinese C5 Corvette Long Tubes(Cheaper on Ebay)
• LS Swap Shorties
  LS Swap Shorties
  • Some sources say the long tubes fit, others say they don't, shorties are my backup but man will they kill low-end torque

Vacuum:

• Vacuum Manifold, Truck Manifold Only has 1 Source Port
  Vacuum Manifold, Truck Manifold Only has 1 Source Port
  • Perks of swapping a vacuum-operated car, to an engine that comes from an all-electric controlled truck. GM was at least kind enough to leave one of the vacuum ports capped on the passenger side of the manifold. Will have to find a nice way to integrate this under the hood.

Clutch

• Spec Stage 1 Clutch
  • Should handle my power levels pretty well, got a killer deal so I'm happy if it lasts for 10K

 

Sorry if I missed it but what trans?
just ordered a pair of c5 longtubes from dna motorsports for $152 shipped. Hopefully it’s just a relatively easy collector swap away from fitting.

 

what junkyard is this in Pittsburgh?

 

Stock 4+3 with John Deere Hy-Gard in the overdrive.
I have the exact long tube headers so ill be sure to post and let you know if and how they fit .

 

Day one of rebuilding down and it went about as expected, long block is in, passenger side mount is giving me some grief with the bolt not lining up but thats a problem I'll solve after an 8 hour pass out break. Headers look like they'll just barely fit on pass side, may need the air box lid to be removed and modified. Drivers side looks like it'll fit with no problems with a few persuasive nudges, they both will definelty need to be slid in from the bottom, no doubt about that.
All in all, the motor install wasn't all that bad, took us about 2 hours to get it in with the trans removed. I decided to go with the second position from the front on the mount adapters, that position requires no clearancing the fire wall to make it fit, but does require the trans to c-beam holes to be elongated towards the front by 0.3 inches. Fuel system got put on hold due to some issues with the harmonic balancer install, but it'll be done today.



Final thing before I get some shut eye, the truck intake looks likes it's gonna take a very slight cowl to make fit, perhaps just shy of 2 inches. For some reason I thought this was gonna require a much larger cowl to fit, but it seems doable thus far.

 

Hello Sir, I need to say this, the purple harness is awesome, I love it! It looks like an alien spaceship, I don’t know if that was your idea, but if it was, you nailed! SO GOOD!

 

Well, I guess it's update time. The cars sitting on the driveway now, I ran out of time at the storage unit. The trailer had this perfect little area for sliding the floor jack in and supporting the the trans while towing so everything made it here safe.
Today and yesterday were a bust, wrestling the trans into place left three of us exhausted only for us to find we'd accidentally stacked an extra shim behind the ToB so I have to undo it all. We ended up removing the drive shaft and C-beam to get that far, and it was still extremely difficult, I'm contemplating removing the engine, assembling outside the car and sliding the whole assembly in from the front. Any thoughts on that?
Also, does anyone know the sizes of the fittings on the 4+3 and in the rad for the OD cooler? One of the fittings siezed and twisted the tube clean off so im looking at changing over to AN lines while I'm working on the clutch hookup.

The C5 headers fit for the most part, the flanges need to be cut off but apart from that they should work. Maybe some minor bashing needed.
The mount plates work like a dream, there was only one major issue with using them in the second position from the front, the batwing oil pan catches on the K-member just ever so slightly, so the K-Member needs a teensy bit of clearancing, a few minutes with the hammer is enough to get about a quarter of an inch clearance. Apart from that, the motor dropped right in, no clearancing the firewall, no cutting the body, windshield wiper has enough room behind the motor so no need for replacing it, you will want to remove it before installing though. A minor issue is the pass side coil bracket gets caught on the HVAC harness, the only work around is to cut off the corner of the bracket so that it clears. The C-beam also needs to be slotted, but that was easy work with a drill and cut-off disk in a Dremel.
Now that I'm back home and don't have a deadline anymore I can take my time and thoroughly document the build and take plenty of pics. It also means I'll be able to get more done throughout the week vs just weekends. I'll be taking a short hiatus before I get back into it, something about 3 consecutive days on cold concrete didn't jive all that well with me and I'm incredibly sore.

 

Another week has gone by and now it's time to update. The motor is no longer in the car, I got tired of wrestling it underneath the car so pulled it out to install the trans. It's gonna stay out for a while and I'm gonna start the harness surgery to splice the LS and Corvette together. Since I no longer have a lease deadline looming over my head and the weather is half-decent, I'm gonna be slowing my role and focusing on the nitty-gritty to make this a reliable swap, as well as making this thread informative. Apart from a couple of things, this build is back to square one so the thread will be pretty close to a step by step.
With that said, onto the build progress for yesterday.
Saturday I focused on getting the engine back out and getting the throwout bearing shimmed correctly, I'm set at 0.062, which is on the tight side but it seems it will put the engagement point at the mid-way of pedal travel after the clutch wears in a bit. I decided to try something new with this build, usually, I use a bleeder repair kit and a female 1/8th NPT to AN adapter, but I found these nifty AN bleed screws that go straight into the hose end, it'll be interesting to see how that works out in the end. Overview of the system is -4AN line, stock master @ 11/16 bore, and a Howe 82870. I think this combo will yield the lowest maintenance and reliable setup for the $$ spent. The stock master gets an M12x1.0 metric bubble flare to AN adapter, and the Howe bearing is threaded for both NPT and -4AN. The remote bleeder is the prementioned AN bleeder on a 2-foot section of hose that'll be cable tied to the trans harness for ease of access. Here are some pictures of the setup and a parts list at the end. As you'll see, I went with 45* hose ends for the two connections on the slave; the 90* fittings I have been too long and put the hose end directly into the wall of the bell housing so I couldn't get a good bend radius on the bleed hose, the 45* rectifies that but it's not ideal. On another note, the stud that came with the throwout bearing is not long enough to support it in its full throw, but from what I've read, the throw on the bearing is plenty and requires a pedal stop, so it should be a non-issue. I'll be 3D printing a plate that will hold the hoses away from the edges as well as some properly fitting clamps to keep everything as abrasion-resistant as possible, this bearing is the type where the bearing body itself moves and pulls the hoses with it. All in the hydro bearing conversion cost me $220 and a few hours of work, the fun part of plumbing it in the car is still to come though.




Parts List
Parts are hyperlinked

• M12X1.0 Bubble Flare to -3AN
  M12X1.0 Bubble Flare to -3AN
• -3AN to -4AN Expanding Fitting
  -3AN to -4AN Expanding Fitting
• -4AN PTFE and Fitting Kit
  -4AN PTFE and Fitting Kit
• -4AN Bleed Adapter
  -4AN Bleed Adapter
• Howe Racing 82870

One last thing, for the LS swapped owners, how did you do you vacuum lines?
I have a vacuum manifold that I can either put inline with the brake booster, or run off the one vacuum fitting on the truck intake on the passenger side.

 

Kicking off the weekend a bit early today, had some time after work so I dove into CAD.
I had previously designed a low-profile 3-bolt to 4-bolt throttle body adapter, but the bolt locations caused non-ideal alignment that would have killed airflow. The new version moves the 92mm TB out and down, and puts it at a 10* angle relative to the face of the intake, which will help with hood clearance. This will be 3D printed, sanded and then sealed with epoxy resin, it's a technique I've used before and am a big fan of as it brings costs way down for air-tight, light and strong parts. The parts are basically hollow and are sealed using two different resins in two stages, a water-thin resin that penetrates the porosity of the 3D printed parts(about 3mm from the previous testing), this stabilizes the part and prevents cold flow under compression, and a thicker resin that fills gaps such as layer lines and polishes to a gasket-ready finish. V2 also adds somewhere in the 180cc range to the volume of the plenum, which inches it ever so closer to the plenum volume of the LS1 and just under the golden 80% of displacement rule.
Here are a couple of pictures that show how the flat design was not ideal for airflow, both are rendered with the truck intake side facing the "camera".
Version 1:

Version 2:

The flat adapter was nowhere close to lined up due to the bolts interfering with each other, V2 should flow more in transient throttle conditions and not have any major velocity issues as V1 would have.
Below are a few more pictures of both designs, they'll both be going up on Thingiverse in the near future when I verify fit and finish.





More to come tomorrow, I start gutting the electrical system and splicing in the LS harness which should be pretty interesting.

 

That’s bad ***. Love the idea of resin coated PLA, but just why not use a resin printer? You can get a decent one for a little over $200 and print that adapter in one step.

 

I thought about it, and have experimented with both resin and SLS printed intakes, but had issues with cracking around the area where the nuts sit, as well as blowouts if and when the engine backfired. A resin-sealed FDM part is the brute force option, it's strong, temperature resistant, and can be hit with a ton of force and not budge or crack. The other thing is I am using brass heat-set threaded inserts to mount the 92mm throttle body, those are much more robust compared to the printed threads of a resin print. The resin print would have a much better sealing surface and not need much post-processing, but I don't think it fits this scenario all that well.
I got caught up in household chores like cutting the grass and decided to spend the rest of the day CAD, I 3D scanned the hood earlier and am letting the computer do its thing, but within the next 10 hours I'll have printed the TB adapter and finished designing the form for the hood cowl. Tomorrow, I'm hopping back into the car to do all the electrical work.

 

Computers been chugging for the last 28 hours and still has a good bit to go, decided to try and get the 3D scan as detailed as possible to be able to accurately model a final cowl version as well as maybe some hood vents. For anyone that's interested there's a snapshot of what the process looks like below. The weird splotches on the hood are unique targets that the software can identify and place in 3D space based on how they distort, they're calibrated to also have known dimensions which drastically cuts down on post-processing required afterward.

As for today's progress, I was able to mate the transmission to the engine for what is hopefully the last time for a while and finish prepping the engine to go back in. The helper I was waiting on to come to move the hood couldn't make it so no access to all I wanted to do, but I did get to redesign the throttle body adapter to add a 96mm ID o-ring that I forgot.

 

That scanner is pretty trick. Had a friend use one to build the enclosure on my boat. Wasn't perfect but was pretty close... it was in the water and just moved too much to be exact. It's well beyond my limited CAD experience. I'm digressing lol. Point is, everything is looking great.

 

How do you feel about helping the C4 community and sharing your 3d model of the stock hood? Keep your modification private of course, but many of us would love to have that stock file