Actually, a lot of Amazon sellers offer rebuilt Q-jets. I can't vouch for the quality of any of 'em. But there are lots of choices. Don't know if your Amazon card can be used to buy from Amazon sellers or not. But the Amazon store card can be used, including interest free, for 6 months.
If you don't mind rigging up the throttle linkage and running the return spring to the front, you can use a Buick or Olds carb. There is even a Chevy truck carb that had a front inlet.
Also, if you don't mind plumbing for a side inlet, they offer a lot of Side inlet models, including the Jet brand, which have a fairly good rep. They also have Jet brand front inlet Q's, though they don't look to have Pontiac type throttle linkage. Might require some riggin, to hook up the throttle cable.
