I've read the other alky posts and don't recall if anyone has stipulated the ideal compression ratio for its use. Iron vs aluminum head? On some recent builds, pump gas motors were pretty close in power to the high compression brothers(11:1 and +). With the 25% + use with alcohol and the procedures required, pump gas was cost effective and simple to use since we all started out using it. My BB injected altered from 40 + years ago ran a heater core as a radiator. At 13:1 with an aluminum head, the motor always wanted more heat. With zoomies, the fumes were not so appealing with a slow staging opponent. I did have some cylinder wall wash issues. Had to send the injectors to Ronco in Blue Bell PA every year to have the lines replaced. They seem to develop cracks. I assume that fuel line quality has increased since then. Without changing the direction of original question, I met 2 guys that were big bracket racers that ran in the 9.50-10.50 range. Pretty consistent. Both used a methanol injection system with their race gas.