383 needs more power

Fisher said
About all you can do is change the cam to something with more lift, thats a pretty small cam anyway. and either port the heads you have or buy a decent set of aftermarket aluminum. Does this motor have headers on it now? What is your main use of this car?

I took a 383 machined in a 440 crank = 426 now. Makes 525 hp and 552 tq. Nice street manners, drives well no complaints.

He's talking about this camshaft.

11-651-47 - XTREME Energy™ Hydraulic Flat Tappet Camshafts with 18736542 Firing Order 4 & 7 swap firing order.

Hardly low lift for a hydraulic flat camshaft. That's a stout camshaft for a stock stroke 383. Which is what we're talkin about here, not a stroker. Apples to oranges and does the OP no good. Lets keep the discussion down to what he HAS so we can better help him. Ok?

To the OP, first off, how does the car RUN? I mean omitting anything you have learned dyno wise? Are you happy with it? Will it smoke tires? Does it accelerate briskly? It may well be fine, because it's possible to lose 100 HP through the drive train.

That said, here's where "I" recommend starting. First, run a compression test and post up the numbers. This will give us a good idea about the static and dynamic compression ratios of the engine. My guess is, it will be 120 or less. We can better advise you with compression test numbers so get crackin and let us know.

You have lots of options. You can taylor the camshaft timing to better match the initial cylinder pressure readings. If they are low, you can advance the camshaft timing. If that engine has stock compression pistons in it, I would put that cam somewhere around 100-102 ICL. But that's getting ahead of ourselves. Lets get those compression test numbers first and we can go from there, ok?