Hello there! Been readin the boards for a while, but I don't post too often.

Well anyways... Recently a 350 tpi out of a wrecked trans-am became available to me. I am told the engine had been swapped in from an 87 Iroc. I believe this would make it an L98 (still not too good with those codes). My first question is, with the trans am available to me for whatever parts I need, would I be able to swap this into an 86 305 tpi (it's an Iroc). Both cars are automatic, and the recipient of this engine has the stock transmission (I do not know the name of it, but it is a 4 speed automatic).

So assuming that it is possible, I would like to ask a few questions. I have read through the posts on this specific board more than I can remember during classes, and on late nights.. but everyone seems to be doing a TBI, or LT1/LS1 swap, or just not specifically what I am doing. Since I do not know a whole lot about engine swaps, I never know if I can take the advice that they were given given the conditions of my swap.

I am planning to rebuild the engine, because it has pretty high mileage, and try to build it up to be exactly what I want it to be all while it's sitting on the engine stand. So far, what I have gathered from these forums is that I want..

1) New rear. I actually just assume I will need one for the 350, but I don't actually know what I have. I believe it is a posi, because both tires spin, or none at all. Is there any way to find out what a 305, tpi, auto, Iroc came with in 86?

3.43's are what seem to be the happy medium between nice grabbage and fuel economy

2) Sub-Frame Connectors seem to be something people highly recommend

3) Hooker 2055 1-5/8" short-tube headers, with their y-pipe, as well as a nice high-flow cat, and cat-back from hooker also.

4) Aluminum driveshaft from a 4th gen

5) MSD Ignition module (any clarification on this would be greatly appreciated. I understand some of the actual engine work, but the electrical system baffles me so far)

6) Heads... This is one of those things that everyone seems to have a different opinion on. I am looking for something that will provide me with some nice low end power, and support somewhere around the 350hp range. Also, would it be better to just port the l98 heads out, or get something else? I am on a fairly tight budget, but I don't mind prolonging the project in order to get the most out of the engine.

7) Cam... Same problem. Any suggestions? I would like to keep this car as my daily driver, but I can deal with relatively low mileage.

8) I want to keep the TPI system, and I want to keep it N/A, possibly larger TB, ported plenum, siamesed runners..

This is all I can think of at the moment. I know it's alot to ask, but does anyone have any suggestions on any of the things I listed, or even something I forgot to list?

Sorry for such a long post, and all of the simultaneous questions, but sometimes I think that after reading all of these posts on engine builds, I just get more and more confused because of the multitude of possibilities.

Thankyou so much to anyone who shares any info with me about this.. I hope to bring respect to the third gen in my home town, and to the campus here at UMD!

 

You're asking good questions, so let's try some good answers.

Rear end: There is a code stamped on the top of the passenger side axle tube. Scrape off the gunk and see what it is (3 characters, numbers & letters). There will probably be something else stamped on there, too, but the 3-character one is the one you want. The Haynes manual has the codes in it. Assuming the rear hasn't been modified, that'll tell you. Check both cars, assuming you can get whatever you want from the donor. BTW, the rears were the same whether 305 or 350 (or V6, for that matter), the only things that changed were ratio and posi/no-posi.

3.42's are the number you're talking about. A good street performance ratio.

Porting stock heads is a good idea. New valve springs to match the cam and screw in studs also a good idea.

Cam - Crane 2032 or Comp XE256 roller version. Either will give good power and will keep the computer happy. Figure on needing a higher stall torque converter to let the engine spin up into the powerband.

For the TPI system, port the plenum, get the shorter siamesed runners, and an adjustable fuel pressure regulator. You probably won't need a larger TB, but a 52mm probably wouldn't hurt anything.

Subframe connectors and poly bushings are a good idea. Boxed lower control arms also good.

Sounds like you're on the right track.

 

Thankyou very much for the reply. You have been very helpful

 

Does anyone else have any input on any of the other items on this list?

 

Been a few days.. I figured I'd bump this up. Any info would be greatly appreciated, thanks.

 

Maybe because you got some very solid answers from a great rescource,,,,,

 

That I did Thanks very much Five7Kid. I was just wondering about some of the other questions, such as reccomendations for ignition components

 

yup five7's got you on the right track.

 

I'd really stick with GM/Delco ignition components...too many problems with aftermarket ignition modules. The external MSD amplifier boxes tend to be helpful, but with a swap I tend to want to keep it simple until the car's up and running.