Tech1, the roll-but-not-scuff concept is probably the intention of the design and the paper test is neat. I wonder if any tests have been run on any possible oil temperature reduction with the roller rockers or is that just a rumor? I have checked with hand cranking that the pushrods easily clear the holes in the head with the 1.6 ratio rockers but maybe the rollers are needed for 1.6 and higher ratios like the 1.7 shown above and the pushrod holes ovaled for the 1.7 ratio? Again I ask whether anyone here knows of failure of the Speedway roller rockers?

Don Shillady
Retired Scientist/teen rodder