new head gaskets & turned crank without marking distributor. can`t find timing

remove number 1 spark plug. hand turn the motor till the piston is at top dead center. you can use a coat hanger or screw driver. once that is done, drop the distributor in with the rotor pointing straight ahead to the front of the truck. number 1 in the cap should be right above the rotor end. Roy

If your truck has the the flat style vortec cap there should be two triangular tabs inside the distributor housing. one has a number 6 and the other has a number 8. Bring the engine up to top dead center on the compression stroke on the number one cylinder. Point the tip of the rotor exactly to the number 8 if a v8 or number 6 if a v6. turn the oil pump shaft if with a long screwdriver if needed to make it drop and seat correctly.