Googling 3978456N returns a bunch of different Chevy V8 engines that use this flywheel. 11" clutch disk. 14" flywheel. 168 tooth, typical for a 12v system. F 29 2 is a date code for June 29 of some year that ends in a 2, like 1952, 1962, 1972, etc. Not saying it wouldn't bolt to your '57 235, but it certainly wasn't born there.
'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.
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