Question is, how much money you got?

350 rebuild is cheap.

383 Stroker = NOT CHEAP.

Any good 383 Machinist is going to hit you for close to a grand.
Cleaning, grinding out the block to let the whirly things go round and round, line bore, head work (you better do this), balancing the whirly parts. And other things.

A cheap base 383 should kick out close to 300 HP, being very subjective and conservative.

Carb? =Money
Intake? = Money
Headers? = Money
Heads = Money

Take a grand, buy good parts, good machinist, and ask a lot of questions and you could get a 400 HP + motor out of it.

Add Nitrous and add 1/3rd HP, but understand the whole thing could go BOOM and you would have....... a pile of sh..!