Hi all I have a question about a carb swap. What I have is a 302 that is running the stock motercraft 300 which has some issuse. So I know a guy that has a Holley 500 that will bolt on but I was wondering what it would do to my gas milage. Right now I'm getting about 9mpg so I want to know if the 500 will help it or hurt it becouse I can't have it go any lower. some information would be welcome thanks.