There is no real need for guesswork. Is the valve cover installed? If not, turn the engine clockwise from the front (normal running direction) until the #6 exhaust valve (last one in line) opens fully and starts to close. When the intake valve (2nd. from the back) just begins to open, drop the distributor in with the rotor pointed to the #1 spark plug wire. You're timed to fire #1, no guesswork at all.

If the valve cover is installed and you don't want to remove it, turn the engine with the #1 spark plug removed and your thumb over the plug hole until you feel compression pressure, then continue turning until the ball and pointer align. Drop the distributor in timed to #1. Either method eliminates the guesswork about which cylinder is on the compression stroke.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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