What roller rockers are correct for "Olds" heads, and how do you tell the difference (dimensions, specs, etc...)? This as opposed to the rockers based on or meant for Ford applications that are "close". What are the effects of using the Ford version vs one designed for Olds geometry. Are the effects only noticed for large-lift applications? Does the head (aka aftermarket heads (particularly the new Edelbrock 61035 heads) vs stock #5s) make a difference?

Thanks.

 

It's really in depth. While Ford rockers are close they don't allow for exact motion across the valve tip. This leads to less than optimal lift translation. I'm most cases as long as you have the pattern across the tip that is centered and relatively narrow it should be ok in most but the demanding all out applications. The other thing is while trying to achieve a good pattern the rockers usually need to be lowered or raised to the point you get interference at the trunion or push rod. Best is to use an Olds rocker such as S5016 from Harland Sharp.

 

I thought that in some cases there was an issue with the Phord rockers rubbing on the spring/.retainer?

 

In my post I was referring more to the geometry in relationship from the trunion to the roller and cup. The problem your talking about is an issue too. On that note the size of the boss around the bearing can also bottom out on the stud hex.