pump gas engine vs. high compression

higher compression = you get more power out of the same amount of fuel. will detonate if the octane is too low or if the build is not a smart build ... quench, cam overlap, aluminum heads, good cooling system, etc. help prevent detonation

lower compression = you can run pump gas with no worries, iron heads, not have to worry about quench, etc. but you will get less power from the fuel (the fuel burns less efficiently).