When the machine shop overhauled my 302 head they used small block Chevy V8 valves. New intake valves measured 1.841" (original was 1.856") and 1.60" exhaust (original was 1.565"). I don't remember what they used for guides. Valve springs are spec’d by GMC at 53-63 pounds of pressure on-seat. The machine shop found some proper diameter springs that measured 65 pounds at installed height. They also supplied the caps and the keepers. Sorry, I don't have part numbers.
Last edited by Bill Hanlon; 03/24/2026 5:22 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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