Even on a stock 273 2 barrel engine. You have to remember a 318 has a very small hydraulic cam with no lift and no duration. 50 hp requires more compression, cam change, as well as the little things that all add up. Still a worthwhile upgrade. The only car I liked with a 2 barrel carb was my 170 slant six. Check the 318 HP in the late 70's when there was a 4 barrel 318 with the same cam and compression as the 2 barrel.
