If your talking about the car in your profile, it is a 289 that came with a hydraulic lift cam from the factory. If that is what you are installing you will need to set the initial lifter preload. To do this you need to find TDC of each cylinder but you also need to make sure you are on the compression stroke and not the exhaust stroke for that cylinder, to do this you can pull spark plugs and watch the piston come up and look at your distributor rotor to make sure it points to same plug wire. Once you have a cylinder at TDC, install push rod, rocker, and nut. As you tighten the nut down, spin the push rod with your fingers. When you get to the point that you feel very slight resistence to spin the push rod you have reached zero clearance. NOTE: You need to pay very close attention as the nut comes against the rocker as it is easy to go past that zero clearance point. Once you find that zero clearance point you will turn the nut an additional 1/2-3/4 turn. Thats it, do both valves for that cylinder and find TDC of the next cylinder in the fireing order.