Hi guys, a while ago, nearly a year, i swapped a 350 into my 305 RS. Since my car is a 1990, I was wondering if I have to change out the ECM or does it have the cop car chip? Also, should I change the TBI injectors too? Do you guys think I'd be better off switching to a carberator or keep it throttle body or what? Another thing that sucks is i don't know all the specs of the engine because i didn't build it, I bought it off a guy who built it. If I remember right since it was so long ago, it was bored .40 over, and it had a pretty decent sized cam on it, and it has a intake manifold for TBI, it has roller rockers. He offered the holley TBI and ECM he had for it but me and my uncle decided not to take it. Well, the engines in, we've got it all hooked but no exhaust on it yet just headers that just so happen to be up agains the floor real hard so i imagine that i need to get a different set of headers. So... should go carb or keep TBI and if i keep TBI should I upgrade it to something better than stock, and if so what should I do, what should I do about the ECM, do i need a new one for the 350? Or if I choose carb what should I do with the extra wires and what not on the harness? I'm an amatuer but a fast learner, and I'd really like to make this baby fast, but I don't want it to be a half baked job, I want it to look very professional. My uncle said that he wasn't too sure with my decision to buy an engine off a guy but after we fired it up he said that it seems to be in good running condition and he said that it is real lopey. he said that its a bigger cam than he thought. the guy told me that he thinks its gettin around 350hp. But who knows. But enough rambling on. what do you guys think I should do?

 

Fast learner? Any good with computers? Learning to burn your own PROM is probably the best way to get the most out of the car with TBI. You probably should have taken the TBI, but hard to say about the computer unless you know exactly what it was.

The only "cop" tuning I'm aware of is the L98 in 3rd gens, and LO5 in Caprices. I believe the Caprices only got TBI, so there might be some help there. But, with whatever the cam is in your engine, it would probably still need some tweaking to get it right.

 

Sounds to me like it'd be easier to put a carb on it. If I put a carb on it what should i do with the extra plugs and wires on the harness? Will I have a problem with VATS security? What do most people do with the wiring harness when they put in a crate engine and put a carb on it and delete the smog controls and what not?

 

If you go carb, it will be simpler up front, but you'll introduce a few complications.

VATS: Shouldn't affect it, but if it does, there's a tech article linked from the thirdgen.org homepage that provides all the info you'll need.

Harness: Forget what "most" people do - do the right thing. The wires you will need can be separated from those you don't without cutting anything. The ECM harness routes to the passenger side fender and through the kick panel. Remove the plastic fender liner in the wheel well, and you can unplug the harness and take it out in one piece, sensors and all.

One "complication" with the carb is the automatic transmission interfaces. The first one is the torque converter lock-up clutch control - it goes through the ECM harness. And, it won't function without the inputs from the engine to the ECM, even if you leave all the harness in place. You'll have to provide a means to lock up the torque converter clutch, or your transmission won't be happy with you very long. You also need to provide proper throttle valve cable operation with the carb linkage, which is easier with the TBI parts than TPI, but may require adapters depending upon the carb you use. Do it wrong, same results as no TCC lock-up. If you have manual transmission, never mind.

 

Thanks alot man, another question, I was reading up a bit about LT1 inake conversions, what are your thoughts on that? Does it sound like a better idea? This car is gonna be a daily driver and i hear that the LT1 intake conversion will give me decent gas mileage and throw down the torque. once again, thanks!

 

I haven't been impressed with the LT1 intake conversion.

LT1 swap - that I will support.

 

ah... I see, so what is it that isn't really impressing you? I want a quick car, but good for daily driving too, thats why I brought up the LT1 conversion. Are there any conversions like the LT1 that you think are any good?

 

http://www.hawksthirdgenparts.com/in...OD&ProdID=1443

is this any good? it comes with the fuel rails but it says to use a LT1 throttle body, so will this really be any different? also do you guys think that this will work with a LT1 ECM and harness?

 

it would work with a tpi ecm and harness and a properly burnt prom. There are a lot of people around that seem to like em, it's a fairly easy swap if you already have tpi, if you don't you basically need to get a tpi harness, sensors, and ecm, plus fuel rails for it, it says it accepts holley fuel rails, and an lt1 tb.