[Sirrotica]

To add to what Cliff has posted about OEM stamped rockers, all the race engines I've built, none had roller rockers, because they weren't allowed per the rules. The Pontiac arms had the correct hardness of all the components, and wore very well. I remember reading that the guy that designed the rocker setup (Clayton Leech) specified the the components were to be cyanide case hardened. Likely a process that is no longer used because of the EPA. The piece ends up with a very hard outer shell for wear resistance, but still maintains the ductility of the core material.

I had one time bought some Manley aftermarket 1.65 rockers because the OEM ones were quite expensive. They promptly pulled the ball down through the stamping, so much for saving money on aftermarket parts. I assume there was no case hardening on those parts, that the OEM parts have.

I ended up throwing them away, and bought the paid through the nose at the dealer for GM parts. Since the GM parts came with the 11/32" pushrods, I also had to upgrade the guide plates to RA IV too. I've run the 1.65 OEM parts on at least 3 engines to date, the've survived perfectly, little to no wear. I've used the OEM rocker arms, and pivot balls on solid cams, as well as solid roller cams with no appreciable wear, and more importantly, no failures.

Oval track engines tend to need to have to have reliable parts due to the fact they are run in a race environment for a much longer period of time. They run for many laps at one time, rather than 10-15 seconds such as drag cars tend to. One season on an oval track engine is much more run time than a drag car gets. They also run at a high temperature for much longer periods, showing how reliable the parts are in an endurance environment.

Since the 70s, all The Pontiac engines I've had, I've never owned a set of roller rocker arms. I've pretty much torture tested the OEM rockers, and never had failures. They've worked on cams into the area of .550 lift, and I realize that as lift is increased, they likely will become a liability, rather than an asset. but at my cam specs they have worked flawlessly. Something to be said for the KISS theory.