In discussion with a race car owner we had different ideas about how the rocker angles change when an engine is fitted with a modified camshaft. My opinion [not theory] was that it does and something has to be done to compensate. Obviously the extra lift of the cam will affect the travel [arc] of the rocker but does the geometry or 'purchase' of the rocker suffer?
When cylinder heads have been excessively machined I've always understood that to restore the rocker angle it is necessary to place spacer shims under the rocker shaft pedestals. The thickness of the shims being the same as the amount removed from the head.
I put it to my race car owner friend that the same mods would need to be done to the engine with the modified cam.
He dismissed my opinion as myth.
I may be "building bridges where there are no rivers" with most of the above but this old head needs to get around it.
Any race car engineers out there with pushrod race engine experience care to contribute?