Hmmm now here’s a riddle. Ordered a crank bolt for that 383, got it in, too small for the crank, walk over to the spare 440 crank perfect fit. WTF? I don’t recall B series have bigger crank balancer bolts?!
difference is the RV 440 and the 383. I think.
BTW, you can usually tell the cast crank by the damper. It will either say
"use on cast crank only" or something similar, or it will have an eccentric
look to the inner hub from the front. The standard thin damper for forged
cranks is concentric in every way.
Good Luck!