Quote:
Originally Posted by berfinroy
at least until designers started commonly using 4 valves per cylinder heads (more jazz) which would be pretty hard to do using pushrods!
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4V per cylinder operated by pushrods are out there...
Duramax 6.6L diesel (Pictured)
6.0L and 6.4L International/Ford
Cummins 24V I-6's
Not as complicated as in may seem, theres rocker bridges that link the valves togather, operated by one rocker per valve set.
Arao enginering makes a 24V head for small block chevys too....
As for Hi-rpm pushrod motors, i can vouch for that as a long time drag racer. I have seen plenty of pushrod V-8s rev north of 10,000rpm!
Our 8.3L ARIAS Pro-Mod Hemi would rev north of 11K crossing the 1/4 mile mark! Thats alot of engine to rev that high!
I concour though, OHC is better for Hi-rpm, just sayin pushrod motors can do it too
One other consideration is, parasitic/frictional losses, more part=more loss.