I have a 91 TBI LO3 with an Edlebrok intake, custom exhaust and 3.73 gears.

Is it possible to replace the stock cam with an LT1 or LT4.

What additional things would I need to do to ensure computer compatibility?

 

any swap that changed the air flow of the engine will cause the computer to need to be changed. since our cars are speed density, they are more touchy to changes that the MAF cars are. the lt4 cams are rather large, not something i would swap without doing heads at the same time. read the DIY-PROM article from traxion on this site, and start reading on teh diy board. see what you have ahead of you for tuning.

 

make sure it is an LT1 cam, you CANT use one from an LS1

 

He is right on this one. You can use any cam from a gen one or two block but not the newer gen 3 (LS1 series) engines. All LT1/LT4 cams have a loger dowel pin on the end of the shaft that needs to be cut off or pressed in. The LS1 cams are completely different in every way shape and form. The production LT4 is about as big as you can go on stock heads. That is with 1.5 roller rockers which puts its lift right around .450".

 

im goin to put lb9 heads which are the 5.0 tpi heads and a lt1 cam with 1.6 roller rockers and put screw in studs on the heads so im going to see like 50 hp gain and a manifold to

 

You will need to have the spring seats machined to accept that cam with 1.6's. If not you will have to do some close measuring to make sure that there isn't any coil bind. Also, are you going to port those heads and tune your own chip. If not you won't see anywhere near 50hp gain. If you fully tune, have a really good port on those TPI heads, or go for an aftermarket brand, and good intake with proper fuel delivery, then you may see 50hp.