Including both our shipping times, probably 2 weeks at most.....yep, just plugged everything in...but, haven't fired it up yet....body's still off car.

 

Dr.Jay did this great TPI writeup:

http://forums.corvetteforum.com/c3-t...l-started.html

I have a modified harness that allowed me to put the computer behind the seats. It runs down the pass side tunnel with some speaker wires(disregard the Pioneer amp under the pass seat, I was just sitting on it!):



The trunk of the harness runs through the old HVAC/AC wiring grommet and sits up against the firewall just about exactly as it looks in the next picture. It fits under the heater box pefectly and just clears the vert's metal trans tunnel bracing. The AC/HVAC wiring now utilizes the vacuum line grommet visible just to the left of the TPI harness in this pic:



These are the lines coming out on the engine side of the firewall:

 

Just my 2 cents here...I own a 71 BB, and an 89 IROC Z 5.7 TPI. Not really sure why you would convert to TPI on an older car unless fuel economy is your primary concern. The performance is not that great, big carb is much better.

 

The 89 Corvette that I had would have kicked the crap out of either Vette I have now, the 76 or the 80...so I have a hard time believing that performance is lacking. Compared to a BB, of COURSE it's not that great. But MY swap is being done because I want the rebuilt engine, EFI is so much smoother and more reliable, easier to start in cold weather...plus, it looks sweet under the hood.......AND for $250 I couldn't really say no!

 

Ok... I drug the donor car home day before yesterday, and got everything all disconnected yesterday with the exception of the tourque converter bolts that almost seem frozen to the flywheel! And they are 1 15mm bolt, and of course I don't have that sized socket in my arsenal! Arrghh! But everything is coming along nicely.

But.........I did run the vin on the donor, and ran into a small "snag" I guess you could say. The kid that I bought the car from said that it's a rebuilt 350 motor, but the vin decodes as a 305! I have not pulled the numbers on the block yet, but I'm hoping that it's NOT a 305 motor. I had bought the whole setup with the thought in the back of my mind that I could just always pull the TPI stuff off and swap it over to the 74 block that I have, but of course that requires swapping heads, distributor, and such. Plus I would need to see if all of the accessories that came with the motor would change over....OH, and let's not forget a 350 ECM prom. So I was little discouraged when I saw that...and never really thought to check that before I bought the engine. It's not too big of a deal, but still not what I was sold.

I know some of the C3's came with a 305 out of California....but my question is this. The car that it's going in is my wife's car...so absolute raw HP is not that big of an issue. I know the 305 would have plenty of scoot to it, maybe so my wife wouldn't get in as much trouble!!! Is the 305 going to be a dog in there? I mean, the 185 stock horse in a Vette 350 seems about the same. Maybe it would be a slight improvement in HP, I dunno. I've got a 305 TBI in my 89 Chevy truck, and it's not the fastest truck on the planet. I'm just needing some moral support and/or input on this one here guys. Feel free to chime in.

Maybe the older 350 block with the TPI goodies swapped over, plus a set of cheap vortec heads would fit the bill??

 

If you bought a 396 rat and found it was just a 350 mouse motor, would it make a difference? This is the same thing that MAY have happened to you - 305 vs. a 350.

FIRST you have to check whether the engine you bought is a 305. If it is, then the seller has probably lied about other things, such as "only 11,000 miles on the engine".

If it is a 305, its not going to be any sort of performance engine because of the 305 heads. You will be better off with the '74 or whatever other 350 engine you have. You can install all of the TPI parts on it (you may have to drill the center bolts on the TPI manifold to match the angle of the mounting bolts on your heads) You will need a different knock sensor and a different chip, which are specific to the 350. Neither is very expensive. You may also need a set of 22 to 24# injectors unless you try to raise the fuel pressure to 48-52 lbs to give it the fuel it needs through 19# injectors. The 22 to 24 # are not too expensive off of ebay (If interested, I have a good set of 24# Ford/Bosch blue tops for $75).

You cannot use vortec heads with TPI unless you get a new manifold from Scroggins-Dickey or Edelbrock. This will cost approx $450.

Keep us informed.

 

Well, the engine gods have smiled upon me tonight. I was able to pull the engine AND trans together as a complete unit from the donor car tonight. It took some "holding my tongue in the right way" to get that to come out. I couldn't get the u-joint off, so I just pulled the trans straight out of the yoke and driveline. I had the donor parked with the front wheels up on the trailer, and the hoist on the trailer as well. After about 10 minutes, she was free and out of the car!!! I'm stoked!!

I was going to leave the transmission in the car and just use the stock TH350, but after thinking about it longer I decided to go with the 700R4 in order to get the overdrive, and I will not have to fool around with a VSS conversion. I'll still need to sort out the whole speedometer cable issue, since the new trans does not have one, so I guess I may still have to get some sort of an adapter for it. Not a biggie.

PLUS....and here is the really good news....the block IS a 350!! It says right on the back of the engine "5.7"!! I was beginning to get a little bummed out, thinking that it was a 5.0, but I don't have to worry about that now. I will need to make sure that I have the right prom in the ECM, as I do not know if the kids changed that over. He SHOULD have, but that doesn't mean he did. I'm sure it would not have run right if he didn't, and who knows, that might be IN PART why he parked it after he blew the rear end out of it. I will be checking all of that, you can be sure of that.

Overall, then engine looks to be in good shape, with the exception of dirt and grease on the sides of the block. I think he may have forgotten to put valve cover gaskets on there! And for some odd reason......the water pump is orange. ?? I guess he couldn't spring for the can of black paint....the water pump from another engine was all that he had....or he really liked an orange water pump on there. Any which way you look at it, it needs a new water pump!! But I am a happy camper tonight, and I got the whole setup wheeled into the garage, wires, transmission and all.

PS....before I pulled the motor out of my Vette, 2 weekends ago, I had never pulled a motor EVER. Plus, I did that by myself, and I got the engine and trans out of the donor by myself! I'm pretty proud of myself, if I do say so....myself! A lot of "firsts" for me here, and I'm just diving in with both feet. So if there are any other first-timers that are thinking of doing stuff like this but are too afraid....DON'T be. If I can do it, ANYONE can do it. Just get your feet wet, and don't be afraid to make mistakes.

 

PS....dumb question.......can someone tell me where I can get information on what to do with the fuseblock/firewall connector? I am obviously not at the point yet, but I'm curious as hell as to HOW the wiring harness is connected to the C3 harness. Just a lot of splicing or what??

Oh...and is there a crossmember that will bolt in to hold the 700R4, or will I need to fabricate that (Lord I hope not).

 

I don't know how much of the harness from the donor car you're using, so that may make a dfference, but one recommendation I would make is to add a separate relay to power all of the switched ignition leads. I used a switched lead from the ignition as a signal wire for the relay, and then ran the larger 12V (the one that powers up when the relay gets the signal) to a fuse block. I've got my injector wires, the HEI power wire, and a couple other things from that rats nest of wires powered off the fuse block.

Also, I would seriously consider buying one of the reprogrammable chip-replacement options rather than just getting one burned. You'll spend a little more up front, but if you decide to mod the engine at all, you'll spend less money than you would getting two custom chips burned.

Good luck!

 

Hmmm....interesting. I am going to use the entire wiring harness if possible. There are only a few things that I am deleting, such as the AC and the A.I.R. injection stuff. Will I really need to have a different chip if everything is the same as what was in the donor? The ignition did not have the VATS system, as there was no resistor on the key. I will be having the ecm run the fans as well. Oh, and I am going to use the transmission that came out of the donor too. I purchased the manual for TPI swaps, Chevrolet TPI and TBI Fuel Injected Engine Swapping, which has provided a lot of very useful information, but not some critical info such as HOW to actually wire up the bulkhead connector to the rest of the car. I've ordered a service manual for the donor car, which should help with the identification of the components, but there is still some info that I need to glean from someone that has done this swap before. Pictures would also be of great benefit.

 

Hey Bruce? What additional wires do I need from under the dash by the fuseblock? I am guessing that I need to diagnostic port, but HOW is that connected? I still have the donor car here for another few days, and I am pulling off fuel lines, brackets, and other misc odds and ends, and I don't want to overlook something that I may need for this conversion. Can you offer any more advice on that?

I've been curious about how to add the SES light into the dash setup on the 76 as well. Just a little hazy on the finer details needed for this swap....but I sure know a HECK of a lot more than I did when I set out on this quest less than 2 weeks ago!! Thanks in advance!!

Trevor

 

There are 3 main power wires going to the computer, two are marked inj1&2 they go through a 7 amp fuse to a steady + right off the alt/horn relay....there is another one on the wiring diagram, that one powers the 5 volt regulator on the computer, and of course activates the system, that one goes to the ignition power source, pink wire.....which if your car has a HEI already will be a plug in, if not, you need rewire your old points setup for the heavy pink wire for the HEI, you can find it coming off your ignition switch on top of the steering column, and down at the fuse box....you maybe even have a tab to slip connector over at the fuse box...

one thing I think you want to do, something I just did as a possible cure for some gremlin that showed very recently, I ran a 10 ga wire from the engine to the metal of the body, directly, and in the wiring, I grounded all the computer grounds to the engine directly....injectors are grounded to engine block directly at the engine....

 

Thanks! Is there a wiring diagram that someone has put together for this swap? It just seems like there are a lot of wires in the bulkhead connector, and I presume a lot of them need to be hooked up, yes? I have not found a source yet that will actually walk me through the connection process with diagrams that are easy to follow. And do you simply cut off the old engine harness, or does it unbolt and separate like the bulkhead connector on the donor car? It just seems odd that there is not a step-by-step manual for this swap...I dunno. I just need to see pics, diagrams, etc, and that will help a lot. I have ordered the factory service manual for the donor, which I am sure will help a lot.

And what do you do with the diagnostic port? Does this come off easily, and is it connected directly to the ECM? I poked my head under the dash, right before it started pouring rain tonight, and it looks like it gets tied in with the dash wiring harness. Am I missing something?? And I DO already have HEI as well.

 

I strongly urge you to go online to jagsthatrun.com and get their TPI swap manual. This covers all of the issues you are asking about, including using the donar cars TPI harness. It was written by someone who has faced all of the problems you are facing, and would be valuable to you.

 

I HAVE that manual, but it does not go into specifics on HOW to actually wire up the car. They address that issue and say that they can't possibly list all of the cars that would get a swap, and to order a service manual from "Helm". They make that plug for the Helm manual about 500 times, so I think they are in "cahoots" with them!

The manual IS good, don't get me wrong, but I need specifics on WHAT needs to be hooked up...HOW it's hooked up....etc. Hopefully when the service manual for the donor car arrives it will tell me more.

 

I didn't know they made non-VATS versions of that combo. So no, you won't need a chip since you're using the combo that the tune was intended for. Get it running as is, ignore the AIR and other codes, and when you decide to swap cams or heads or the whole top end, get an emulator then.

Also, I hooked the SES light wire to the seat belt warning bulb in my dash. I took off the OBD-I dash connector and hard wired a USB ALDL cable so I can monitor the engine with my laptop (I use TunerPro).

 

Ok...just figured I'd post some photos of the engine that was pulled out of the donor. Aside from the poor re-paint on the engine block and some grease and grime, she's all there and in good condition. I can not BELIEVE how fricking heavy that combo is when pulled as a unit! Thank goodness for a quality engine hoist!!

First, this is the engine that was pulled out. As you can see, it's clearly not a Corvette engine, based on the brackets and exhaust manifolds. It all fit in the engine bay alright, but you spot the bracket setup right off.







And here's the new one.....please excuse the greasy mess on the side of the block and the clutter in the background!









A little messing around on the runners shows that they should polish up nicely...after the dents are removed. Doh!

 

Here is a link to a post with my TPI "primer". As far as I know there are no '91s without VATS. It may have an earlier column and they just put a resistor in the VATS plug which is a common fix for failing VATS. You will want to have the chip burnt to remove VATS, EGR, and anything else you aren't going to use. I would keep canister purge, but it is commonly removed. Even if the chip is from a 305 IROC, when it is reburnt, it can easily be changed to the 350 version. Good luck with it, I am very happy with mine.

http://forums.corvetteforum.com/c3-g...o-my-73-a.html

 

 

So has anyone that has done this swap deleted the A/C compressor? I was pulling brackets off today so I can paint the block, and I noticed that the A/C bracket is all combined with the smog pump bracket and the tensioner is part of the bracket that I was going to permanently delete. I know there is a delete bracket for the A/C, but if I get rid of the main bracket, I lose the ability to tighten the serpentine belt. The alternator is on a fixed bracket, so does that mean I need to get some sort of adjustable bracket?? I'm sort of bummed, since I really like the factory tensioner, as it's really easy to use, but unless I somehow butcher the factory bracket, I can't retain that feature. Any ideas?