[carbking]

Originally Posted by lust4speed

Scarcity causes higher prices. And these things should be rare the way they came apart. The first year's casting was terrible as mentioned previously. You even looked at it wrong and another screw would strip out. Maybe it was the fact that other carbs took great abuse, and we just treated the carb the same way and it didn't like it. My original carb was beyond repair by 1973. By then, it had oversized screws in about half the holes, had the fuel inlet repair kit, the bottom plug repair kit, and didn't have a decent sealing surface left. The spread-bore Holley 800 CFM carb that replaced it in 1973 is still in use today. A very early quadrajet in good condition today has to be a very, very rare item.

During 1969, 1970, and 1971 (maybe later as well), Rochester offered bowl kits. These were new UNSTAMPED bowls. The parts books listed generic bowls for many applications. The factory tech was supposed to either stamp the number of the carb which the bowl was replacing; or many simply used one of the "dyno" label makers and used the stick on label.

Since I don't restamp (or in this case stamp), I once set a new bowl in a vice, and starting changing the fuel filter (this was a 1970 bowl). With no tension on the fuel line (there wasn't a fuel line!), I was able to change the fuel filter 11 times before the threads became not useable!!!!!! This is the major design flaw with any of the Q-Jets. All others can be overcome for reasonably stock engines by a carburetor restorer. Since this feature was NEVER remedied, I have wondered if it was not a design flaw, but rather a design to increase sales??? The problem here is the 7/8 by 20 thread, which allows tremendous torque to be applied on individual threads. Add in the pseudo-mechanics who are in love with teflon paste (a lubricant) and the pressure exceeds the structural strength of the zinc alloy. As for the other screws pulling, we have to install maybe one heli-coil per 20 carburetors; and we built ONLY those produced before 1975. I will admit not liking to work on the 1965 or 1966 units, as they have other issues (not related to the zinc alloy body).

Rochesters are not the only units to have thread pulling woes; while I haven't rebuilt a Holley in MANY years, I cannot recall ever rebuilding one that did not require at least one heli-coil in the area holding the pump housing (generally 3 or 4). Areas requiring maintenance (ie the fuel filter or the pump diaphragm) just give problems.

We always suggest to our customers that they remove the filter in the front of the Q-Jet, and replace it with an inline filter. A little prevention saves a world of problems.

Jon.