Some people in this forum are running "Shaft Mounted" Rockers on their very high output Boosted Engines. This article does a very good job of explaining rocker arm geometry on a shaft mounted rocker arm. Once you understand the theory a person could relate to the "state of the art" Shaft systems and what similar changes would do to their set-ups.

http://www.eatonbalancing.com/blog/2007/12/10/rocker-arm-geometry/


http://www.eatonbalancing.com/blog/...-ratio-by-varying-the-length-of-the-pushrods/

Tom Vaught

 

in for later

 

thanks

 

great site

 

Same thing applies to stud-mounted rockers. I ended up with a 8.15" pushrod vs. the stock 7.8" on my engine. The combination of small base circle, high lift and rocker ratio, and lash caps really changed the requirements. The difference of 1/4" in pushrod length took the rocker from scubbing all the way across the valve head to only moving about 1/16". I gained a bit more lift as well!

Short Pushrod:
#ad


Long Pushrod:
#ad