The 270 was used in larger trucks since WW2, but 55.2 was the first year it was used in smaller trucks.[ <-- This is a mistake on my part, corrected a few posts down. ] 1952 was the first year for the Hydra-Matic. 6 cylinder 55.2 GMCs stayed with the earlier 6 volt positive ground electrics while V8s went to 12 volt negative ground. All were 12 volt in 56.
Last edited by Bill Hanlon; 05/24/2026 3:57 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.
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