A 283 QJ carb would be about as scarce as a chicken with lips. There was a Pontiac 250 OHC six with a QJ, but those carbs are extremely hard to find and expensive when they're located. A 292 with a little bit of overbore will be right in the ballpark for a 305 carb.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!