Yup... there is a 90% chance that old Q-puke has a vacuum leak at the shafts. A shaft rebush can be done by the shade tree mechanic... but is a little more involved than just a rebuild.
You couldn't pay me to use an Edlebrock/AFB carb. A Holley 650 Spread Bore vacuum secondary carb will bolt right on to the stock manifold. It will also bolt to an Edelbrock Performer (non-RPM) without an adapter.
If you run the Performer RPM you will need an adapter to run the Q-puke or any Spread Bore carb. The squarebore Edelpuke will bolt up right to the RPM... as will all the Holley squarebores. Like a Holley 1850... which is 600cfm.
Now... you're gonna hear all the Holley haters chime in on how you have to screw with a Holley carb all the time to get it to "run right". That is simply not true. Dialing in a Holley is just as easy dialing in a Edelbrock/AFB. Heck most of the "Avenger" series of Holley carbs are great right out of the box.
Clear as mud?
Gary