The "camelhump", or "double bump" heads were the high performance offering for smallblocks. Those heads with slightly larger valves were used on the famous fuel injection motors for 375 HP, and with the smaller valves they still could make 350 factory horsepower in the Novas. They had larger ports than the lopo heads too. They were all I ever used, and I could hang with the big block muscle cars on any given day.