It must just be the pictures. but it looks to me like valves would hit the non-dished area of the pistons at the end of the exhaust stroke/start of the intake stroke. The dished part of the piston doesn't look wide enough to provide space for the valves.
'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.
