This is a "12 volt" (168 tooth) flywheel. A "6 volt" (139 tooth) flywheel has a lesser number of teeth in the same dimension. You should be able to take this measurement without turning the engine.

I also scribed and painted white marks at 120 degrees and 240 degrees for TDC of cylinder pairs 2&5 and 3&4.
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Last edited by Bill Hanlon; 11/24/2024 4:40 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.