The problem with pressed in bottle-neck studs pulling out is just one of the problems. If it was, you could merely pin them.
If you increase the spring load more than 110 lb. on the seats and 280 lb. open, you risk snapping the studs at the bottle neck.
If you have an aftermarket camshaft with a cam lobe base circle diameter smaller than 1.330", you will not be able to set the lifter pre-load at 20 lb. torque.
You should therefore convert to fully adjustable valve train with 7/16"-20 or 3/8"-24 rocker studs. Cam grinders can get up to a maximum of .470" valve lift (.313" lobe lift) with a 1.330" cam lobe base circle and still use a non-adjustable valve train. It pays them to do so because they can sell more camshafts that way since their customers do not have to install screw in rocker studs and convert to a fully adjustable valve train. Cam grinders have discovered it is risky to have more than .450" valve lift (.300" lobe lift) with a 1.330" base circle or you risk breaking the stock bottle neck rocker studs. The cam grinders let you find that out the hard way after they have your money.
Last edited by MouseFink; 05-01-2013 at 10:00 AM.