The 283's never had Q-jet carbs, because they hadn't been invented yet. It's a great carburetor, but you will definitely need to do some rejetting. The jets will need to be richer, not leaner, however, and the float level will need to be set a little higher. Small-displacement engines develop less venturi vacuum, because they're flowing less air volume at any particular RPM, so the jets need to be larger. Get a set of numbered drill bits, and start increasint the main jet size a few thousandths at a time until the throttle response and power suits you. A flow bench and a chassis dyno will help a lot during your experimentation, if you happen to have those items. Otherwise, it's all "cut and try" work. I've seen a .005" change in jet size get a 20 HP increase during a dyno run.
A Quadrajet calibrated for a 305 engine will be pretty close to the jet sizes you need for the 283, and might work OK with just a higher float level setting. You will probably need to tighten the air valve spring a little to prevent bogging when the secondary throttles open, also. I'd try that approach first.
Jerry
