What would 7.562 ball and ball pushrods be from?

Marcohotrod said
the pushrods used by steve d in the hot rod 318 with a hydraulic flat lifter was 7.650"

I saw that It's only a 1/32 more than the ones i have. What would be the trouble i would run into if i used this set on a hydraulic flat tappet, to much preload??

Jake