yes when it is lugged under load,free reeving is no problem .it worked with a 600 holey when i had a rv cam in it ,just wanted a bit less gas .this is a smaller carb ,kinda like a economaster ,the same carb work's just perfect on my dad's 1940 1/2 4 speed with a 235 .the on extra performance part's he has is fenton headers with a offenhauser intake .it howl's on it.my vacuum is good i think about12 inches at idle ,the vacume advance work's also .
