Hello, I'm new here and I have a 91 RS 305 TBI I'm wanting to swap out for a 350 TPI set up and Trans. I actually have a donor 87 IROC Z (which is to far gone to save as far as the body and suspension goes) and my questions are "What problems could I encounter in doing this?" "could I change out the serpentine belt system from my 91 to the 87 engine?"and "what are some good upgrades to throw at this project?" (application for car is DD that could keep up with/kill a muskrat or Honda). any input would be appreciated. Thanks!

 

Im swapping a 1988 camaro 305tbi to a 1987 formula 350tpi. Bought engine bay harness & pcm for tpi. Bought larger volume fuel pump to support injectors. Will serpentine belt system swap from 88' camaro to the 87'formula motor?

 

I yes it will, I asked a friend at work and you can do it. You'll just need to change all your pulleys over

 

What is your reason for wanting TPI? Do you have the TPI setup? You could go 350 TBI very easily and save a bunch of wiring. To do TPI, you will need a 7730 ECM, repin your wiring harness and get the appropriate sensors. You should probably read the stickies about repining your harness for TPI if that is the route you want to take. As far as modifications, cam, heads and intake, along with a good exhaust system. If you don't have the TPI setup yet, you might want to look at alternative intake systems. With some work, the Chinese HSR is said to be a good low cost alternative. Of course, all the same mods can be done on a TBI 350 and make more than enough power to kill some muskrats!

 

The reason Im going with the TPI setup is cause the IROC Z Im getting has a running 350 TPI so I figure if I got it might as well go for it. I'm also using this as a learning experience too. And I have done some looking into the TBI 350, but my TBI system has got some issues. To drive the car I have had to advance the timing 29 degrees and leave the timing wire unplugged. With the wire plugged in the engine barely runs, and back spins before it dies. Me and a friend at work spent a week trying to trace down the issue to no avail.....which sucked. but its drivable so I just went with it. Also I like the upgrade ideas, I decided a cam, headers, and a flowmaster super 10 muffler might just do the job. do you have any cam suggestions cause I really don't know exactly what to go with here. Ive cammed trucks but cars are new to me if that makes sense.

 

UPDATE: I've had the block bored over .060 installed trwl2252af pistons on stock rods. Installed 276hr14 comp cam. Cam states dizzy gear must be a Composite but reviews say that gear wont work with hv oil pump. I have a Melling 55hv. Anyone running a composite with a hv pump. Im at the point of closing up the bottom end but if i cant use a hv pump with this plastic gear might have to put a std vol pump in. Idk. Ideas????? Has anyone used this cam with the stock dizzy gear or composite with hv pump???

 

UPDATE: ok Ive got the engine, trans., and wiring harness out of my IROC, and I have started to remove the 305 from my 91 RS. the only foreseeable problem I have is after I get the new harness installed, im not sure how the new harness will work with the other harnesses in the car. Anyone have any thoughts???

 

You best bet would be to buy a 90-92 engine harness.

https://www.thirdgen.org/forums/tpi/...ml#post5108410

 

Well ive got a few issues the TPI system I have is a MAF and its 4 years behind my car. I have gone through the wiring diagrams for the the 91 and 87 ECMs and I found quite a few similarities between the two and minor differences. I have been looking into painless performance products to see if they could edit my 87 harness to work with my 91 car.

 

It would be wayyyy cheaper to buy a 90-92 engine harness and swap over to speed density than having Painless even touch your 87 wiring harness. Sometimes the most expensive way to do something is to try to use a part because you already have it.

 

So with a speed density system all I have to change over is what pocket said and thats it ? And of course get a map sensor. And I dont need another ECM?

 

You do need a different ECM, the current ecm you have is commonly called a '165 (part number 1227165). You need a '730 (1227730). Neither of those are that expensive. You can also then resell the 165, wiring harness, MAF, etc to someone with a MAF car. I would just post up a wanted ad on this site. With either setup you are going to need a custom PROM to work with what you've done to the motor.

I still believe that it will cheaper (and without a doubt easier) then attempting to retrofit the 87 stuff into the 91. I personally am planning out a 305 TBI to 350 TPI swap for my 1992 Firebird convertible and after looking at what it would take to retrofit the MAF harness I already had, I bought the 90-92 wiring harness. So I am just saying, I am practising what I preach

You actually don't need a MAP sensor, you can re-use the TBI one.

 

Well I will definitely look into that and post results for sure. Ive actually come a pretty good ways with doing that retro fit but with what youre saying im liking that idea better.

 

Came across this in the classifieds, thought you might be interested:

https://www.thirdgen.org/forums/engi...ty-engine.html

 

Well I did some looking and I came across a company called tempe speed and performance. They're building me a custom wiring harness that will allow me to keep my mass air flow sensor and everything else will work as it should. Cost was $375 for the harness and $150 for burning a new chip for the TPI ECM. I'm having the chip set up for performance and they're deleting the air injection and EGR. Reason for EGR delete is due to location cause it'll be a pain to replace. And also theyre going to configure the chip for the new cam I'm upgrading to as well. As far as other endeavors go I finished up a port polish job on my heads and im planning going .010 over on valve size and ill choose pistons accordingly. The block is still at the machine shop and the heads went back yesterday so other than that, thats it for now

 

well a lot has happened here recently. I've now upgraded from the 74CC L98 heads and gone to LPC performance aluminum heads with 200 CC intake runner, 2.02 int., 1.80 exh., and 64CC chamber. Forged aluminum dome top pistons that's bumping me up to 10.63:1 compression ratio. also added AFR head bolts, and AFR rod bolts. And its bored .030 over, and I added roller rockers. $$$$$$

 

Ok, so after looking at the intake and heads it looks like if we port the intake to match the heads we are going to have a very minimal sealing surface for our gaskets. is there any advise anyone can offer here?? a different intake is being considered, but funds are becoming tighter