Hello there I have just put in a rebuilt big block in my mud drag pickup, and I had to reset the valves after the break in period cause I had weak valve springs in for the first half hour of run time. Anyways I was wandering how come my vacuum reading bounces around from 13- 15 inches at idle. I have to pull 15 inches of vacuum for tech in. I passed the first tech in. I was wandering if I don't have the valves set right. or something. No vacuum leaks around carb or brake booster that I can tell. Just need some suggestions. When I set the valves I just turned the motor over until I thought the pushrod was done moving down then tighted up while turning the pushrod when I felt resistance I went another 3/4 turn. First time I set valves so tell me if I'm wrong. Thanks