I've been doing a lot of reading here concerning this swap, but I still have a few questions that I'd be grateful if someone in the know could answer.

I have an 89 Formula 5-speed with a 305 TBI. I've finally decided to swap in a 350 TPI L98 motor (basically the stock 350 TPI motor for 89) that a friend says he can track down for me.

My understanding is that this should be a direct swap with only a few minor issues. Please correct me if I'm wrong on any of the areas.

1. The computer (ECU) is the same but may need to be re-tuned.
2. Wiring harness is the same.
3. Should fit in the existing mounts.
4. Should mate up to the existing transmission. (I know the stock 5-speed transmission is light for the motor, but I plan on swapping that at a later date for another 5-gear when funds permit).
5. Existing rear should handle the engine.

Are there any other parts (related to the swap) that differ between the two that I'd need to pick up, such as sensors, fuel lines, electrical stuff, etc?

I may throw a rebuild kit at the motor depending on the shape it's in, but that's outside the scope of my questions.

Any help would be appreciated -- I'm being overwhelmed by the information here and I've been out of the F-body world for a couple of decades.

Thanks.

 

esentially you will need everything that you can get with the TPI. Although the only TPI specific parts that you to get are the air filter system, and injector wiring, self modify, the TPS, and IAC wiring will need to be extended. and of corse a new chip. the ECU will work because the TPI's were batch fire, meaning that the right bank fires, the the left bank fires, back and forth. the TBI has only 2 injectors which fire alternately, therefor you can break out these wires to run 4 injectors each. hope that makes sense. you have to get into an LT1 before you see sequential injection

 

Two more probably-dumb questions --

1. will the exhaust system for the 305 work with the 350 L98 or am I buying a new exhaust system, too?

2. How about the radiator? I would guess the 350 came with more cores than the 305, but that's just a guess.

Thanks

 

#1 yes you use the 305 units, a small block is a small block. if you want to change them get a set off of an LT1 they flow almost as good as shorty headers with out the hassle of headers

#2 there really is no difference in radiators, but get it cleaned or go to a parts house and get a HD replacement. these cars are prone to heat issues, I went as far as to get a Ford Mark 5 fan - moves almost twice the air, on low. be sure to check the amp draw when running, the first one pulled 45 amps, the second is pulling 17 amps

 

i too plan a 350 tpi swap, i know ls1s are more performance and carb'd 350s would be easier, but something about the tpi engines, they have that x factor

 

that is what I'm talkin about!!!!!!

 

lets be honest thirdgens are quick but most people love them because of the aesthetics and my god tpis when all clean and new are such a damn pretty engine