Mopar use to sell two different versions of there beaded steel head gaskest for the wedge motors, one for the 361,383,413 and 426W motors that was .022 thick with the smaller bore size for those motors. The other larger bore size was for the 440 , it was .017 thick so maybe the engineers reduce the thickness on those to help keep the compression up Try seeing if any of the vendors out there still have any of the original head gaskest for the smaller bore motors