interchanging heads

[80monteturbo]

i have a 1980 carb/turbo monte carlo and i was goin to buy an extra set of heads to port and polish. i found a pair but i didnt know if all 3.8 heads are the same for the turbo charged engines.(sfi to carb heads) so if someone can help me out and let me know if i can put newer heads off a 3.8 engine on mine.

also if someone can tell me the stock valve size that comes in the turbo monte carlo 3.8

thanks