I've dealt with a few olds q-jets (their the same thing) and they are a pain the the ass, but if you can tune them just perfectly it will be the best carb you'll ever own, but if you want easy tuning, get a holley. The Q-Jets usually, at least the ones I've worked on where all 750cfm from the factory, which means it'll outflow that little 600cfm edelbrock you replace it with. Just read up on them they can be tuned to do anything you want, make power, or fuel economy (usually how they where tuned from the factory), you just have to learn what it takes to make it just right.