72 340

Yes as others have said. The 340 cast crank is decent too. Its not the same as a 318 cast crank and the balance is different then a 360. It is lighter than the forged crank and for a street car works just fine. I have one in my 340 that is neutral balanced.

That said, until you see the crank, it won't be a 100% guarantee its not forged. Someone could have needed a balancer, went by the year and got one for a cast crank and put it on.