273 Rockers on a 1971 340

nm9stheham said

But at 30-50 psi at the gauge, there will be nothing like 30-50 psi in the shafts.... Maybe 5 psi...10 psi.... Really a lot lower. That's the way it was designed to be with the 'oiling interruptor' setup in the cam path. The whole rocker oiling setup is a bunch of leaks made to just get dribbles of
oil where needed LOL .... which is why it starts to fall apart with high RPM use.

What I wanted the OP to know is, if he put in banana grooves and got one a bit wide, then don't freak out. He says he is not pushing this engine hard.

Click to expand...

This is exactly correct. The shafts and rockers are the last parts to get oil. While the dribble system (and the oil cloud that is floating around in the valve covers) will oil mostly stock stuff, it doesn't take much with an agressive lobe to start killing parts.

That's the reason why I use HV pumps and keep the idle oil pressure above 40 hot. It's not a Chevy. They don't oil the same, contrary to all the whiz bangs in gym shorts.

Low idle oil volume (and the pressure loss due to low volume) is hard on shafts and rockers.