Originally Posted By: THE FRENCHTOWN FLYER
 Originally Posted By: CNC-Dude #5585
I think it's a "theoretical" 1.5 ratio


CNC-Dude, You bring up a good point. Usually the theoretical ratio is more than what the actual rocker arm delivers. Aftermarket rocker arm suppliers seem to have figured this out and often give you "a little extra ratio" to bring the lift-at-the-valve more into line what the theoretical ratio should have delivered.


Some stock production Ford "1.5" rockers I dyno tested actually delivered lift-at-the-valve equivalent to 1.39:1. When I switched to a Crane aluminum roller rocker lift-at-the-valve was actually 1.50 times the lobe lift. Power increased. Imagine that!!!

FORD 300 inline six - THE BEST KEPT SECRET IN DRAG RACING!