Trying to build a 383, what top end components such as heads, intake and tb would be get me 425 rwhp.

 

Livernois Stage III's, FAST92 (ported by Mamo) and NW throttle body.

my .02

 

425 is easy on 383. I almost make that on 346ci stock bottom. Raise the bar. I have a friend making 47x and running upper 10's with TSP 5'3's, unported Fast 90/90, and MS4. Don't know for sure but think he is milled to 59cc and pistons have 4cc valve relief. I'll ask tomorrow

 

i'd be shootin for about 490rwhp or so, the stock 346ls1 with h/c is an easy 425rwhp. See what Texas speed, and other good shops have to say...

 

You can acheive your goals very easily, a 383 is capable of more power than that.

Some heads and a mild cam and your where you want to be. I would look for used cnc'ed ls6 heads and save some money.

 

Hands down, 205 AFR, Mamo ported 90 (92), Should net you around 430-450, depending on how radical the cam.