1972 350.....Using a solid lifter,Comp Magnum Roller tip rockers, studs, guide plates and Comp push rod length checker I am getting .100" length difference between the intake and exhaust push rod length on all cylinders. Is this correct? I thought they should be the same length?

 

Perhaps same length for only hydraulic lifters?

 

If you have more lift on the exhaust, that might account for the different readings.
I'd call Comp, and ask if you should run two different lengths, or split it down the middle.

 

Have the valves ever been replaced?