Question About Difference In Pulley Diameter?

[69sixpackbee]

I have a couple of 402's and both have power steering pulleys. The one in my truck now (original '72 engine) has a power steering pulley that is the same diameter as the other crank pullys. The one I am putting in (1971 engine) has a pulley that is about 1" in diameter smaller. Could this possibly be one for a higher revving engine? The pushrods in the '71 engine are 3/8" dia. and has valve springs that have inner damper coils. My orig. engine has 5/16" pushrods and single coil springs. I am curious about this. I will put my original P/S pulley on the engine I am putting in my truck and will figure out what to do with the other.