Does a 73 the crankshaft pully on a cast crank 340 have a different bolt pattern?
The change was in 1972. '71 and older used the one staggered hole so the pulley will only mount one way. The '72 and newer balancers/pulleys used an even pattern so the pulley can mount any of 6 ways. Nothing wrong with slotting the one hole to make any combo work......in fact.....most of the later replacement pulleys you got from Mother Mopar have the slot built in.