Not sure about the main journals, but the PD crank will have larger bearing journals than the 1Y. That means you will have to use PD rods. However, the PD rods will have larger pin ends than the pistons in your 1Y (25 vs. 24mm) or something like that. Also, the PD crank has a sprocket built into it for running the chain driven oil pump. In other words, it would probably be more trouble than its worth. You could either convert your crank nose to accept the newer style pulley, or use a friction washer between the standard pulley and the crank nose. These are supposed to make all the difference.