The GMC Master parts books say the 663062 1 1/4" plugs fit the back of the head on 228, 236, 248, 256, 270, 302, 360, 426 and 502 cubic inch six cylinder engines made from 1939 through 1960.
'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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