icanfixall
Official GMM hand model
I found this really interesting information in my International Engine Service Manual. It states that when the heads are going back on and you start installing the rocker arms the motor must be turned past top dead center just about half the distance between that mark and the 12 oclock position. So if you looking at the front of the motor and its timed to the marks now turn the crank half way from that point to 12 oclock and the valves wont hit a piston when you tightening down the bolts. I never knew this. I'll be assembling my motor in a week or two so I'll try this and post back what I feel....