A few misconceptions in this thread:
(1) Rochester started producing the Q-Jet in 1965.
(2) Carter produced millions of Q-Jets under license from GM FOR O.E. GM applications. The lettering on the drivers side of the bowl differed, but the same identification number was used. Carter and Rochester with the same identification number use the same parts.
(3) Q-Jet numbering is normally 7 or 8 digits beginning with 70 (7 digit) or 170 (8 digit). EXCEPTIONS:
(3-A) Most O.E. Q-Jet ID numbers, whether Rochester or Carter from the late 1960's were FIVE digits (the leading 70 was omitted). Just append 70 to the front and use it as a 7 digit number
(3-B) Carter also made aftermarket Q-Jets. These have the Carter style number (4 digits, followed by the letter S as in (S)am).
(4) The clones are NOT Carters. They are a redesign of the AFB done when Carter was owned by Federal Mogul (Carters were too expensive, FM wanted to sell them cheaper than Holleys, AND THEY COULD with the new ones!) We sent our initial order back to FM, as did many Carter distributors.
(5) Bart is mostly correct on the range on the CARTER AFB, however, they were still used as O.E. on marine and high performance export (no smog) as late as 1980.
(6) The Competition Series Carters were made in 500, 625, and 750 versions, but there was no 625 chokeless, manual choke only on the 625
(7) There are two excellent books on the Q-Jet, plus a third one with good information.
(7-A) Rochester Carburetors by Doug Roe and Bill Fisher (Doug was the design engineer on the Q-Jet)
(7-B) Q-Jets (maybe not exact title) by Cliff Ruggles (Mr. Q-Jet) - among the top 5 carburetor books I have read in the last 55 years!
(7-C) There is excellent Q-Jet information in the book by Jim Hand on Pontiac engines (see Joe H.'s post above)
(8) The Rochester well-plugs on the 1965-1967 models did leak. The issue was resolved with the 1968 models.
And finally: Bart mentioned the Carter AVS which is the worst 4-barrel Carter ever built (Opinion). Chevrolet tried it one year, and discontinued it. Chrysler couldn't pass smog emission without it in the 68-71 years. As soon as the TQ was available, Chrysler discontinued the AVS. Today, they are exceptionally valuable (to collectors only) because virtually every one was junked 7 nano-seconds after the factory warranty expired.
Carter offered it, at least in the catalogs, as aftermarket in 1972 (we were a Carter distributor at the time), but I have NEVER seen one, or spoken with anyone who has seen one!
Jon
Last edited by carbking; 05/26/2019 10:37 PM.
