Otto - there are a number of possible formats of identification numbers STAMPED on a Q-Jet.
78 buckshop is correct about location (pump side, center casting vertical stamping about an inch from the rear of the carb).
If the carb were produced by Rochester these could be:
(1) 7 digit beginning with a 70nnnnn (most 1965~1975)
(2) 8 digit beginning with a 170nnnnn (1976 and newer)
(3) 5 digit beginning with a 2 (on some 1968 and 1969 carbs the leading 70 was omitted.
If the carburetor was produced by Carter, then the 3 above are possible plus:
(4) 5 characters ENDING with the letter S as in (Sam) nnnnS
There are a number of "number decoders" on the internet (and to my embarrassment, one of the first published was by me almost 30 years ago). Mine was published with a caviat, which I have not seen on others.
The decoder is approximately 95 percent correct WHICH MEANS IT IS APPROXIMATELY 5 PERCENT WRONG. IGNORE THE DECODERS AND LOOK UP THE NUMBER!
Buckshot, like you, most enthusiasts refer to drivers side and passengers side, but since some folks drive on the wrong side of the road
the carb companies referred to pump side and choke side.
Jon
