Hank: This picture is of the original #2 piston in my 1952 228 when I pulled the head for a valve job almost 10 years ago. All 6 original pistons are still installed and running well 40,000 miles later. These pistons are flat at the manifold side for a little less than 1/2 the diameter, then slop up into a flat dome across the rest of the piston top. Don't know if this is what you are looking for, but the GMC Master Parts Book says the same pistons were used from 1939 through 52.
'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.
