360 magnum troubles

Im wondering if he has a huge vacuum leak and has adjusted the carb to idle with it? buddy installed an OOTB Edelbrock without the rear plug installed (why do they even ship it like that?) and it was like that, would idle after turning every screw but no rev. normally on a out of the box holley, the throttle blades uncover the transition slots about as far as they are wide, to make a perfect square. then you sort of work the carb settings around that constant. But used could have all sorts of mods to it.Are all your vacuum ports plugged in that carb? the accelerator pump arm should just touch (wiggle the link arm and tighten screw until you feel it contact) and then back off about 1/8 turn. .031 shooters are pretty common on a 750. Does it have a good power valve? what color is the plastic accelerator pump cam on the throttle shaft? Used Holleys are dangerous like that: they are so modular that you can get one that has 12 things altered from OOTB settings. What port do you have your HEI tied into? Is it in fact getting manifold vacuum off that port? dont run ported vacuum (would have the spud over the throttle blades). suck the vacuum hose of the distributor and watch the advance plate, does it in fact move, and does it hold when you plug the line? A good way to get to know your car.....and go get yourself $3.44 vacuum gauge. loads of info from that little tool. Mini Dial Air vacuum Pressure Gauge Scale Black HP | eBay