I need to know wut size do I need to get the push rod holes drilled to for 1.6 RR? This is for vortec heads. Thanks

 

I'm assuming you mean the guide slots in the head and not the actual hole in the pushrod

 

Coupla ways to go about it...

If your heads have the slots that fit tight to the push rods ( I don't think so, but you might) then you can get the "Louis tool" from Comp http://www.summitracing.com/parts/CCA-4710/ with a 5/16" bit, and continue to use the non-self-aligning rockers, if that's what you've got.

Or, you can just go to town with about a ½" bit, and make sure you drill more toward the rocker stud; and use either guide plates or self-aligning rockers.

Best way depends on what you have now and what your goals are.

 

Uh, guess those would be "self-aligning" rockers, then, right?

I may not get out enough, but I don't recall hearing that self-aligning rocker type heads need to have the holes enlarged for 1.6:1 rockers.