School me in Rocker Shaft Shimming.

Lash caps will move the rocker towards the exhaust side, the opposite way he needs to go. Shimming the shaft up will move the rocker tip toward the middle of the engine(inside). You dont need a tapered shim to do this, std shims work just fine.

The other option is to use shorter valves if you even have that option, or a different set of rockers.

Whats the head/ rocker combo?