hi my name is john. i own a 94 chevy s10 blazer Tahoe LT 4x4 4.3L vortec cpi. i had to change headgaskets and i forgot to mark anything and set to tdc before taking anything apart. cant seem to find tdc now, and i dont know which timing mark is tdc and if someone can give me some info or give me step by step it would help so much.

 

Remove the #1 spark plug,insert a pencil (dont drop it in there!) and have someone turn the crank with a socket wrench until the piston pushes the pencil up,right when it start to go back down move the crank the other way until the pencil moves back up. Then pull off the distributor cap and check the rotor,move the ditributor until the rotor is on top of #1. I think i got that right,done it before to check timing lol.