The quadrajet is an often-overlooked carburetor. It is a wonderful carburetor for the street, and can be modified for racing or autocross. The biggest problem with the Q-Jet is that GM never sold them aftermarket, and never tried to market individual performance parts. If one were going to install a Q-Jet, one from an O.E. application of similiar displacement is a good idea. Pontiac used a Q-Jet on the Sprint option OHC 6 in 1966 through 1969. The 1966 and 1967 were 230 CID; the 1968 and 1969 were 250 CID. The design of the 1968 and 1969 carburetors is better than the earlier design. There is an excellent book on Rochester carburetors, called 'Rochester Carburetors' written by Doug Roe and Bill Fisher, published by H.P. Books.
One need not be intimidated by having to change the travel of throttle linkage. If the linkage pulls to open and needs to push (or the other way), simply machine a hole in the throttle arm on the other side of the throttle shaft (if the present hole is on the bottom, bore one on the top). Like a child's seesaw, this will reverse the travel.
If the travel needs to change ninety degrees (at right angles) it is still no big deal. Simply machine a bolt to set where the throttle linkage and carburetor linkage cross. The bolt should be machined to have a smooth shaft of three-eighths inch ABOVE the bolt. Now machine a piece of flat steel stock in the shape of the letter 'L' with the legs of the 'L' each two inches long. Bore three holes in the 'L'; one at the end of each leg, and one in the 'heel' of the 'L'. Slip the center hole of the 'L' over the bolt and attach the throttle linkage to one end and the carburetor linkage to the other. Moving the throttle linkage will cause the 'L' to rotate, thus moving the carburetor linkage. Bore a hole in the top of the smooth shaft above the 'L', and install a cotter pin to retain the 'L'.
If none of this makes sense, give me a call during normal business hours.
Jon.
