Not sure what you consider High RPM, but A fellow racer I race with, runs a chevy. He started with a race gas and carb (950 I think) that was custom build to his engine specs. Switch over to an alcohol carb (another 950, pretty sure, custom built to his specs). He picked up a few small numbers in 60' and maybe 3-4 hundredths in the 1/8. He switched to ron's toilet over the winter and picked up another 3-4 hundredths in the 1/8, but said throttle response is unreal with the toilet. That was all on track data. This past winter he freshened up his combo and dyno'd it with the gas carb, alcohol carb and toilet all on the same day. I forget the actual numbers but the gas and alcohol carb where within 10-15hp of each other and the toilet made just a little more, but he said the torque curve was better with the toilet. Each combo will like things differently but if the carb either gas or alcohol are tune properly they will preform just about the same IMO. I think he turns that combo to like 6500-6800ish its a 434.