Nicks Garage 383 build

I don't know. I don't run a dyno for a living, so all I can do is guess. BUT, I'd say a good stout 383 with some good worked heads would be capable of 5 bills. I'm sure there are some guys here who've had some fast 383 cars and some still may.
full agreement. i did a 383 for a guy about 15 years ago, nothing wild style just a good solid build. summit forged slugs and machine work for an honest 10:1, old school isky 509/292, the heads were 906's that were full boat done up by DLI along with a performer RPM and a holley 780 with headers.

he didn't want to run it on the dyno, but i drove and rode in the 65 belvedere it was installed in and it hauled the mail.

however, a few years later the "needs mas" bug bit and he wanted to mix it up so he had me put on a tunnel ram with pair of afbs. besides tuning the set up for decent street manners no other changes were made and he had me run it on the chassis dyno where it clicked off a respectable low 390's before the imposed 5500 redline (his arbitrary #). i was bummed it didn't hit the magic 400 (and i'm sure there was more in it with another 1K) but if you extrapolate the data, that would indicate it was making damn near 500 at the crank.

so absolutley capable, but like anything getting there is a matter of compression and heads which don't come cheap or easy.