[Anthony]

I don't know about the cup/ball size being wrong,

but, with the ball and cup pushrods, you need to make sure the cup part of the pushrod doesn't bind on full lift on the side closest to the rocker shaft. The cup can bind against the underside of the rocker. You need to check every rocker arm for clearence. G. Anderson told me with the Dove rockers, you should have at least 3 threads showing below the rocker on the ball stud to make sure you have enough clearence. You may need to run 0.100" shorter pushrods.

Comp Cams FE rockers are made by Dove for them.

427 heads have wider spaced valves than 390/428 heads, both the intake and exhaust valves are farther from the centerline of the chamber, therefore the rockers need to be spaced differently. With edelbrock heads, the Intake valve is spaced from the centerline of the chamber like a 427 head. The exhaust valve is spaced like a 428 head.