I replace the headgaskets and can't get the valve timing back right I got the compression up TDC and the dist. and rotor button line up I went by the firing order 18436572 to get the valve lash out as I tighten the rocker arm bolts then turn 3/4 turn to center the pushrods. What I need to know is what is the right way to set valve timing and the dist. and rotor button the engine trieds to start but won't crank up it's got plenty fire and gas. Please help if any know about 5.7 vortec engine valve adjustment. Thank You.