To be honest I dont think you could get the shorter
chain on, its designed for a block that the mains line bored,
moving the crank closer to the cam. That being said,
if you measure the distance now then move the cam
gear up by .005 (with the chain on)would tell you
if you could get away with the shorter chain. You
might have to do this off of the engine. But if you
look at the amount of slack you have now and split
that in half thats, it would be if you have the
shorter chain... without even going to the short
chain