273 -318 swap information needed

If you want to use the early water pump / timing cover setup on the later engine, you may? run into trouble with the later balancer, which is required for the 318. IE the timing marks will need to be redone, and the balancer may? be larger diameter I'm not sure. You would have to fabricate a different timing pointer which is not that difficult. Also if the 318 balancer is thicker front to rear, the original 273 pulley stack may have to be shimmed at the water pump, and possibly at the alternator. Again, not very difficult