I have one(1972 also) I built for my 1963 Fury, I'm going to tell the local streeters it is and old 413 industrial truck motor that runs pretty good 4.150 stroke, 7.100 long BB chevy type I beam rods, 440 Spurce heads and RPM inatke with a 850 CFM Pro System double pumper, I had it bore to 4.250 after sonic testing it, I wanted some cylinder wall left for future use if needed I think I could have had it bore to 4,320 safely but maybe not, that was a long time ago and I haven't went out to the shop to see if I still have that sonic sheet or not