Crank-Balancer-Flexplate?
I don't know if there are any little differences between marine and auto applications, but the photo below will help determine if it's cast or forged. Cars had cast cranks in '73 340's.
"IF everything else is the same, a forged crank would require a neutral balancer /damper and flexplate. But if you start changing anything, like rods & pistons, you need to rebalance. Factory balance jobs weren't very precise, just "good enough", so it wouldn't be a bad idea to rebalance everything anyway.
I don't know if there are any little differences between marine and auto applications, but the photo below will help determine if it's cast or forged. Cars had cast cranks in '73 340's.
"IF everything else is the same, a forged crank would require a neutral balancer /damper and flexplate. But if you start changing anything, like rods & pistons, you need to rebalance. Factory balance jobs weren't very precise, just "good enough", so it wouldn't be a bad idea to rebalance everything anyway.