[mr0077]

Rick, I gather that since all the FEs had the same bore spacing, that the 391s were cast with thicker cylinder walls, and could take the overbore from 4.05" to 4.13", but after that only a max of 0.030" overbore is recommended (although the 68-69 428s supposedly had thicker walls). Glad your motor turned out to be a good one.