Hello all!
I am new to the forum and as you can see from the subjecy I am about to swap a 90 firebird TPI 350 into my 91 Camaro 305 TBI.
The good thing is I have a donor car "saved" at a salvage yard. I would like to know what all I will need (besides ECM, fuel pump, and wiring harness) and any other things I need to know before I take this project on.
~Thanks

If it attaches to the engine, get it out of the donor car.

What were you thinking with regard to the exhaust system?

As far as exhaust my car has the single pipe crossover to dual outlet muffler (flowmaster) I have been planning to keep the system I have now.

So would you suggest getting the tranny too? And do you know if in 91 the tranny was electronic shift or not? If it isn't we have a police interceptor 700r4 tranny that needs rebuilt that I would use instead

Your transmission will be fine, although the torque converter in the TPI car might work a little better with the TPI engine.

Your exhaust will be inadequate. Either get the exhaust off of the donor car, or go for aftermarket headers, cat, and exhaust for that application.

3rd gens did not get electronically controlled transmissions. The torque converter lockup is controlled by the ECM, but that's all.

Well I plan on taking the tranny because it has a LOT less miles on it than mine. Why will the exhaust work if I changed everything from the engine back to the cat?

Also I have questions about the ECM. I have heard that I need to change both the chip and controller, is that true? And whereabouts is this located?

if your flowmaster kit is 2.5" you should change it, but if you picked up the 3" flowmaster kit (measure the I pipe not the tails) you should be fine change back to the cat.

The ECM is tucked up in the dash above the passenger feet panel. You need to get that, as well as the harness that goes through the kick panel to the fenderwell. Do that, you'll save yourself a bunch of hassle and you won't have to do anything with the chip.

TBI exhaust is horrible from the exhaust ports on the heads all the way to the rear bumper. If any of the exhaust you currently has is for the TBI application, either factory or aftermarket stuff, change it.

good good
I think that just about answers any questions I have for now, if I come up with any more I will be sure to post them. Thanks to both of you
:yourock:
and hopefully after all is said and done there will be more of this

im like in this same situation. i got a '91 z28 with a blown tpi 305. im looking to replace it with a 350 tpi with my current stock FI setup. i got $4000 to spend on the engine body and paint. ive called around looking for a shop to do everything as far as the engine. i got one guy who said he had an engine from a '93 suburban that he said would work. i was kinda skeptical about that but he said he'll get the engine in there for $1400 including the price of the engine. but anyway i call today and they say they dont do "mods" that they only replace whats in there. anyway back to the drawing board. i need a 350 tpi longblock and installation. anyone know how i should go about this?

do i buy an engine and go the home swap route? or continue the wild goose chase of finding a shop that even has the motor i want in the first place? i live in lancaster, ca and im not gettin anywhere... anyone got any ideas?

Well, I would try calling to find an engine first, but only if you have the tools to do the job. If you do not have the proper tools that make the job easier I would just call some garages.

Good luck finding a 350 TPI they are getting rare, at least here in Missouri.

i found a dismantler that has 2 good running 350 longblocks... and the owner says he knows a guy, that'll do the install for $300-$400. its either that or it looks like im getting stuck with a rebuilt 305 tpi. since i have 2 camaros... i guess i'll just save some money and get a 350 for my '87, which is actually a '82 pace car replica, got lucky with the stock 3.23 posi rear end it came with. so im thinking and engine and tranny for that, edlebrock intake and holley carb and it should move pretty smooth. what do you guys think... or maybe i'll have enough left over for a good 'built' 350 and 700r tranny for my carbed camaro.

i need a wiring harness and ecm for my 305 tbi and was wondering if u were willing to sell urs if u havent cut it all up.

Well I plan not to sell the harness or the engine, I would much rather keep them. Sorry.
I do have a question for everyone else though... can the harness be adapted over for use on the TPI without major mods, or will that even work at all?
the reason is that the yard I got it from cut the ECM wires and seem to have damaged some small wires that could be fixed, but I would much rather try to use the original harness because it seems to be in much better shape, in fact it has never been touched.

Also the starter off the 305 should work for the 350, right? I know that on other newer GM trucks that sometimes V6 starters were used on 350's.

Hey everybody!
Here real soon I will be starting to replace my 305,
unfortunately the wiring harness for the TPI is damaged very badly. The question is will I be able to adapt the TBI wiring to the TPI very easily? Also I know I have to change the fuel pump, the amount of work to change the in-tank pump is unbelievable, would it work to install an external fuel pump up by the engine itself to increase the pressure for the TPI?
Thanks for any help in advance!

Can anyone help at all? Any help about the fuel pump would be greatly appreciated

You could do the pump that way, but you'd still need to power the TBI in-tank pump. Powering two pumps may turn out to be more hassle than dropping the tank.

I had a bud who re-pinned a TBI harness to TPI. Spent several weeks doing it. I'd keep looking for a TPI harness, or get one from Painless.

Well, the TPI harness was cut (against my instruction) when it was taken out of the donor car. The wires were cut where the wires come in to the ECM and some of the wires on the lower end were burned. Although the injector and intake wires were unharmed except for the ECM bundle.
Thanks for the insight on the fuel pump. Why is it that you say it might be harder to run both at once?
I'll take a look at Painless, I talked to a GM dealer about a harness.... they only have new harnesses for manual transmissions in stock in my area.

Is there any difference between the automatic and manual wiring harnesses? Because I noticed that Painless doesn't ask anything about the tranmission.

Also I noticed on Painless' FAQ that it says that an engine will not run if transplanted into another car with the original steering column, now I have the entire computer to the new engine but I have my steering column systems original. Will I have to buy a bypass?

The fuel pump circuit is designed for one pump. If you try to run two, you'll have to make up another circuit like the original for the 2nd pump.

The main difference between auto and manual tranny harnesses is the leg that goes down to the tranny. Beyond that, I can't say about the Painless harness from personal experience, but it sounds like they're talking about the VATS system, which they don't support. I wouldn't think you'd have a problem with that as long as you kept the original system you have now, but I can't say that for sure.

Thank you so much for your help, I owe you a lot!

What part of MO are u from? If u live in KC i might be able to get u a harness. If u havent already gotten one. I know a guy that has a couple thirdgens, not sure if they are tpi cars or not.

Im gona be doin a 350 swap soon too.

Well, I am in jefferson county, basically Hillsboro. And no I haven't been able to find one, we have looked at close to ten salvage yards and have come up with nothing. It seems that TPI is rather rare in my area and in the Ozarks. There are a few more places I can look for a harness, but I still might be interested if you can get me one, just so you know I need one that has a MAF sensor plug and the 9th injector... I ended up with a first gen TPI. That wouldn't be too bad to ship from there. Thanks either way!