The way you used will work, but the must accurate way would be using a piston stop. You can find a bolt with the same threads as your spark plugs, and thread it into the combustion chamber (while the piston is down) so that about 1"-1.5" is in the chamber. BY HAND (obviously) by hand, turn the engine over until the bolt stops the piston. Mark the balancer at this point. Turn the engine by hand backwards now so that the piston goes down, then back up and is stopped by the bolt again. Mark this position on the balancer. Remove the bolt and turn the engine so you can see both marks. Measure the distance between the two marks. Exactly halfway between the marks will be TDC.
This work because you are marking a certain degrees before TDC, then marking the same degrees after TDC, so TDC is right in the middle.
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67 Fastback - Arctic White Pearl paint
351W ,Trick Flow Aluminum Heads, Edelbrock TorkerII, Comp. Cam, Performance Automatic C-4 Trans, 3.55 gears, Front Disc Brakes, 1-1/8" Fr. 3/4" rear sway bars.
My 351W Fastback
