I'm not as knowledgable as Mike or some of the others on here but i used to run a .670 roller 280 at .050 dur with 6 pack pistons, 76 cc RPM's snd steel shim head gaskets and they cleared fine.
I run the .590 with the same heads now but with dome pistons and felpros. I clayed the pistons on both.
BTW, love your 66 Fury, you see very few 65-6 at the strip. I used to have a 66 Fury 111 with a 383.
Mick