Hughes rockers

As far as shimming side to side, I used hughes shim kit and rocker shaft hold down kit. The shafts get torqued down and measurements are taken for side to side clearance using a feeler gauge with the rockers roller being as centered as possible over the valve. They give you recommended clearances. This helps the rocker to not put any unnecessary side pressures upon the valve stem through its stroke causing wear. The ideal rocker opens the valve in a perfect linear path