Originally Posted by talon73ta
yes , yes, yes, and yes
and of course you could always place bb olds heads to for fun...
What he said. With stock 403 pistons (with the soup-bowl sized dish), the early 350 heads will bump compression to something reasonable. I would not use these small chamber heads if you plan to use flattop pistons, however. Note that the 350 heads can be cut for the 2.070/1.625 valves used on the big block Olds.
The other option, if you do plan to switch pistons, is the big block Olds heads. These have bigger valves and ports but the same 80-ish CC chambers as the stock 403 heads. Flattops solve that problem. Since the 400 cu in big block used these heads, the 403 cu in small block should like them also. The larger ports limit you to certain intakes that have enough meat for port matching (Performer RPM is one).
And with any early Olds head onto a 403, you will need to open the head bolt holes in the heads. Early motors used 7/16" head bolts, but the 403 (and all 1977-1990 Olds motors) used 1/2" head bolts.