Okay its a 1987 transam with tuned port injection and its a 350. was it orignally a 305? Anyways I just want to add some more power, somewhere around 400hp would be good. No clue what its making now. Whats the bang for the buck? besides nitrous

 

Well, this is a very open question.

About the fact that it was a 350 or 305 originally: AFAIK, All 350s came with the 9 bolt rear end and an 700R4 automatic. (as my car is)

Are you talking about 400Hp at the drive wheels or at the crank?
There is about an 17 to 20% lose due to an auto drivetrain, just for your info. But this makes a BIG difference.

Next, you probably have less than 200Hp at the drive wheels, maybe about 190RWHp at best. You are talking about alot of major changes to your car.

So, how much do you want to spend?

 

It's been stated more than once that all the power in an SBC is either restricted by or produced by the heads and cam.

That's a fairly old idea, and since it was first uttered it has become apparent that there a few other places to gain some power and efficiency, probably just not as much as can be controlled by the cam and heads.

You might be surprised what you can find just in here: