You will need a 379 Flywheel for a bolt on installation or an early 62-63 478 flywheel that can be modified. The 432 Flywheel is much larger in diameter and won't fit in the light duty truck bell housing. The other alternative is a custom Flywheel which is the route I chose but it must be balanced with the whole reciprocating assembly, a pic of the custom flywheel is included here