Pushrod oiling - do I need it?

OMM Thank you for the clarification. The bolt holes on the heads I am using are sufficient diameter so no need for me to do anything to the stud or hole. If it was too tight I would definitely enlarge the hole .0025” or whatever. At least I know to check for it now.

If this were a dedicated race engine I’d probably tube the lifter gallery, block the timed cam bearing feeds and install a crossover line from the #4 to the #2 feeds for full-time oiling. In that case T&D rockers would be required for pushrod oiling.

My engine is nowhere near the level of performance you’re dealing with though so I’m not concerned with the stud being a problem. 7,000 rpm would be about the max I would turn and that would only be for a few seconds anyway. Sustained rpm would be a different story but this is a street car which will see part throttle operation 90% of the time.

I also still don’t believe the step in the bolt is there for added capacity because there’s really not a whole lot of volume involved. Again, my gut tells me it’s for dampening the timed pulses from the cam journal feed. And if you switch to pushrod oiling the stud no longer matters anyway.