If you are building a pump gas engine definitely go with the dished piston. I have the KB745 forged step dish pistons in my sb stroker. With pistons at zero deck, .039" head gaskets, and eddy heads milled to 62cc I have 10.3:1 compression. Without milling the heads it would have been 9.8:1 compression; probably would have run on 89 octane.