I believe the 1971 Stage1 carburetor is 7041242. 7041243 is manual transmission 455. All the 455 carburetors in 1971 are 800 CFM. There are 2 other Q-jets for 350 engines in 1971, they are 750 CFM.
The #5 in the 5th digit indicates your carb was for California emissions. It can easily be upgraded for your application. https://cliffshighperformance.com/articles/quadrajet-casting-number-chart