So the 71 and earlier Buick quadrajets had a 3/4 inch fuel inlet (where the fuel filter sits), whereas the 72 and up had a 7/8 inlet. The earlier versions had a o-ring that went on the outside of the filter housing. So did the 72s have an internal o-ring to keep the fuel filter housing from leaking? Thanks.
65 thru 1971 will be 7/8"-20 threads except for most Marine and some Service Replacement units. ALL 7/8"-20 housings seal at front of the carb and bottom of the nut as shown in your pic. 1972-up were 1"-20 threads and seal on the bottom of the fuel filter housing with the white seal. They 1"-20 set-up is a lot better arrangement as the threads are dry and don't erode away like the early variety. The ONLY way the later style gets stripped out is when they are inadvertently cross-threaded by the installer. I've installed several thousand heli-coils to date, and have only done a couple dozen of the 1"-20 variety.......
Thanks Cliff. Pulled the 72 apart and there was no gasket, but figured it should have one and the only logical place was inside.
