i have a late 70s 350 with 882 heads a 268xe cam a performer intake, and a 600 edelbrock carb (1405). i really would like to have a guesstimate as to how much power.

How much compression? I'd assume in the 8.5:1 range.

What are you using for exhaust? Headers?

What intake? Performer?

just the regular performer for now, and soon to be headers right now its got manifolds

Ok, with small headers, low compression and a performer intake you could make somewhere in the 250hp range.