I don't understand your "would fit in a 1952 battery are of a 1962 chevy 3/4 ton", but ....
Assuming the 850cca battery is in good shape, I'd make sure that ...
1. The battery positive cable is corrosion free on both ends and is 00 wire size.
2. The battery negative cable is corrosion free on both ends, is attached to the engine (one of the starter bolts is best) and is 00 wire size.
If that doesn't resolve your slow crank problem the next step is replacing the starter switch.
'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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