3.31” Crankshafts

StreetSleeper said
Are poly 318 crankshafts: are they interchangeable with LA- does that include any difficulties ?

Not all 273 cranks are forged correct?

Would a 1960’s forged 273 crank need much metal (Mallory) attached to the crankshaft if hypereutectic (lightweight) pistons and I beam aftermarket rods were used in a 318?

Would a 1960’s forged 318 crank need much metal (mallory) attached to the crankshaft if hypereutectic (lightweight) pistons and I beam aftermarket rods were used in a 340?

Am shopping, and I want to know all the options. Thanks

'62 and later poly 318 cranks will work in an LA 273/318/340 engine. Just rebalance. Don't use the '61 and older as they have extended 8 bolt flanges.
273 cranks were forged from '64-7. '68-9 273 cranks were forged (and the same crank as a 318 those years)
Adding Mallory Metal will depend on which reciprocating parts are being used. Sometimes it's just a matter of some minor grinding/drilling....other times it's adding various amounts of MM.