I've got an engine that I am removing the Vortec heads from and replacing with some 041 heads (casting 3947041) that I had in the garage. This is to facilitate putting an EGR manifold on (which I also already have) and passing smog - please don't dog me for removing the vortecs. Anyway, two questions: 1) Is the pushrod length the same between the old (pre-86) heads and the vortecs? 2) Is there any reason I could not use the self-aligning rocker arms from the vortecs on the old heads? The studs are the same diameter, and they *appear* to line up properly.