IMHO, 3/4 of a turn past zero lash on a SBC or BBC is perfect. Manuals will tell you one full turn after zero lash which is OK but IMHO, puts maximum pressure on the valve train components. My rule of thumb is 1/2 turn past zero lash on a racing engine and 3/4 turn past zero lash for a street engine. Now my procedure that I've used on countless Chevy engines in the past 50+ years: 1. If at all possible, warm the engine up completely before adjusting the lifters. 2. Loosen one rocker arm nut until that lifter/rocker arm just starts ticking. Slowly tighten the rocker arm nut until it just stops ticking. STOP! Wait ten seconds and SLOWLY tighten the rocker arm nut 1/4 of a turn. STOP! Wait ten seconds and slowly adjust the rocker arm nut one more 1/4 turn. Either stop adjusting the lifters at 1/2 or 3/4 of a turn. Repeat for all the lifters on the engine. I've NEVER had a cam wear a lobe out or had valve train failure using this method. BUT I also check valve spring coil bind and degree my cams in.