Don, since 1/4 mile needs to have four turns in it before it becomes a race track, I'm not terribly familiar with drag cars. I believe the vent to the headers is more to eliminate explosive vapors by burning them than for any power boost. Any alcohol/nitromethane mix that gets past the piston rings, combined with lubricating oil turns into a compound chemically similar to nitroglycerine in a very short time. That's why we used to change oil between runs on the alcohol-powered drag cars a few years ago. Now, they change engines after one pass. Producing thousands of horsepower for a few seconds tends to make top fueler engines about as reuseable as toilet paper!
Jerry
