I've never tried to use high-lift rockers on a stovebolt engine, but it's pretty common to use a 1.6:1 ratio rocker instead of a 1.5 on a Chevy V-8. To do it right, it's necessary to move the center of the rocker stud about 1/16" toward the intake manifold. This corrects the tendency of the longer rocker to put a side load onto the valve stem and wear out valve guides. It also reduces the friction loss of side pressure on the valve stem. If a customer insists on setting up a set of small block heads for 1.6 rockers, I charge an extra $300.00 labor on the head work for the machining involved in moving the rockers and increasing the clearance for the pushrods.
Jerry
