A QJ for a 250 will run just a bit rich on a 292, due to the extra air volume of another 40+ cubic inches flowing through it. On the other extreme, a carb for a 305 Chevy or a 307 Olds V8 will run very slightly lean since a bit less air will be flowing. At low to moderate RPM, the jetting should be pretty close with either option. The Quadrajet will be a much better choice than a small-bore Edelbrock or something similar, even with an adapter plate, because of the small-diameter, 3-step primary venturis and the massive secondaries with the air valve control to avoid over-carbureting the engine at WOT.
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
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