I have a '90 Camaro RS with the 305 LO3, 700R4, 3.42 gears and 170 pathetic factory horsepower. I want to put in an LT1 intake manifold, LT1 cam, headers and y-pipe, gut the cat, Flowmaster cat-back, K-N filter and a custom chip. How much HP would be expected out of the 305?

 

230

 

the 305 TPI came stock with 230hp. This is an LT1 manifold, with an LT1 cam and headers with a tune. should make more than 230

 

Well I had headers and a dyno tune and new fuel system and only had 146 to the wheels..... So id say no more then 240 or 250.

 

how can you equip a TBI car with an LT1 manifold???

 

I assume it wont use TBI any more.

 

the 90-92 305tpi 5 speed had 230 stock. TPI cars had better heads as well.
I do know that you can get a 91 305TBI to run a 14.7 with LT1 cam, 3.42 gears, Carb base with TBI spacer, K&N Filter and Top, headers, good y-pipe, 3" cat back, no cat, since that is what I ran in my friends 91 Firebird.

 

Just keep the TBI if you're keeping the heads, you're swapping off alot of stuff but still keeping a huge bottleneck with the swirl ports. You should be fine with the cam, TBI mods, and tune.

 

A 350 (5.7 liter) LT1 Fcar factory power rating was 275 to 285 fwhp depending on the model year.

Adjusting the power output for the ratio of displacement, the 350 to your 305:

275*305/350 = 240 hp

If you used a better exhaust than the factory LT1 used, then you might get another 5 to 10 hp. The K&N filter will only give you a power gain if it's within a ducted cold air stream, so 0 to 10 hp for it.

Summary: you might have as low as 245 fwhp or as high as 260 fwhp depending on what mods you make and how well tuned the engine is. If the tuning isn't good, your numbers will be a lot lower. HTH.

 

Thanks a lot for all your inputs. I have a much better idea of where I'll be with all of this. I think my best bet if Im going to spend all this money, I might as well swap out the 305 and get a 350, which will put me at a much higher baseline HP. I'll get the 350 block and heads and swap on the other stuff. by the way, it is possible to put an LT1 manifold on a GEN 1 SBC with minor mods, but it will bolt on.