Re: 4 Barell Holley
yup 4 bbl Holley under air cleaner assy.(what yr, model vehichle?) And also yup on fuel economy, keep your foot outta throttle and 2 mains are fine, put your foot into it and secondarys HELP boost power but rob mpg. If you have choice, get a 4 bbl Holley wih vacuum secondaries, better mpg. I had a 600 that worked great on small block(289) Ford.