I built a 4.15 stroke .030 over hemi in a 66 block. Crank, rods, and piston set was available to me with CD of piston that supported 10 to 1 based on block decking and gasket choice. Even with the 4.15 stroke with mopar journals you have clearance issues to resolve. If your going to stroke bigger than it is a crank with chevy journals, with a stock block, otherwise you have block work to do in my opinion. A blue printed stock hemi motor will make plenty of torque and power. So to me, if it is not for racing, cost and penis size is what determines how big a motor you build if using original stock block. The more you over bore a 57 year old block the more risk to a crack/leak in my opinion.