I think a 4.375 bore with 4.375 storke makes 526 C.I., I've built one of those motors. If you make the bore 4.380 that makes 527 C.I. with the 4.375 stroke. I would build another one of those motors with a stock block but I would use the 2.200 rod journal sizes now with the 7.100 BB chevy type rods

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)