Isky Rocker Arms

Hey guys, well we got the 430 home last week and started to tear it down. We learned that it used to be on a drag boat that ran an Algon injection unit. It still had the drive key on the engine. When I took apart the heads and the valve train, i noticed some pretty trick stuff about this engine. For one the valve train is completely aftermarket. Pushrods, the solid lifters, the valve springs, of course the cam. But i noticed the rocker arms are also Isky. How do I check to see if they are 1.5or1.75(6) i know isky made the larger ratio arms available i just dont know how to id them. Hope all have a great weekend.

Thanks
Marc