\6 swap question

According to the Mopar 6 cylinder manual, the only engine affected by the crankshaft flange change was the 170 CID. They say all 198 & 225 used the larger flange.

The best heavy duty crankshaft (same source) comes from the truck. The forged crank was phased out at the end of the 76 model run. The two cranks are not interchangeable (balance issues). In the stamping on the block look for 225E for a cast crank engine.

IMHO, having a cast crank engine may not be such a bad thing. It depends on how the car is to be used and what kind of power do you expect to get from the engine. Though the forged crank is the stronger of the two types, its mass works against it when the engine revs up. The cast crank should rev up quicker than the forged crank, all else being equal.