for marine use the Q jet are very good abit better then the holley for mild use . a Q jet will take some dirt were the holley will not take any . less gaskets for the Q jets. but it was EZ to get tune up parts for holley jets power valves etc over the Q jets. that is why alot of guy went to the holleys .i like the themo quads the Q jets will get good milage .like other have said. if you keep your foot out of the back door GOOWAAAhhhh they sound some thing like that when they hit