C3 1969 carb gasket

[Jimmy B.]

When I removed the original 7029204 quadrajet from my stock intake manifold (1969 aluminum intake 427/390 hp), I found a base gasket, stainless baffle (gasket), then another base gasket. Can someone verify if this is correct or should I have a base basket on the intake, then the stainless baffle and then the carburetor itself and not the 2nd base gasket? Yes I did look in my poor reproduced copy of the AIM.

Thanks in advance for your help. Reason for removal of carburetor--inlet fitting stripped and gas squirting onto intake mainifold. Yikes!!!
Jim Blakely #3742

[Joe L.]

Re: C3 1969 carb gasket

Jim------

There should be only 1 gasket and 1 stainless steel shield. The gasket goes on the manifold, then the shield, and finally the carburetor.

If you plug the carb heat slot holes (as you should) the importance of the order I described above becomes less and your carburetor will last a lot longer.

[Jim T.]

Re: C3 1969 carb gasket

Jimmy don't know if it is still avialable today, but way back in the early 70's my QJet had a problem with the inlet fitting. A adaptor was used that would screw into the inlet of the my QJet and the gas line would screw into the adaptor. No leaks after that, change that to external leaks. Still have my 70's Qjet with the adaptor fitting. Saving it for whoever ends up with the car someday in case they want it.

[Joe L.]

Re: C3 1969 carb gasket

Jim and Jimmy-----

Inlet fitting problems on a Q-Jet are very common. In fact, it's the only problem that ever caused me to be stranded in my 1969. I pulled into Tonopah, NV at about 5:00PM on a Saturday afternoon (right after the only 2 auto parts stores in town had closed until Monday morning). I discovered the fuel leak problem when I was checking the oil. I had to stay in Tonopah until Monday when I could get the "fixings" at the auto parts store. The whole thing was my own fault; I had forewarnings of this problem and I should have dealt with it promptly.

The problem is almost always caused by "erosion" of the threads in the carburetor float bowl into which the fitting threads.

There are quite a few different "fixes" for the problem. The one I used was the slightly oversize, self-tapping inlet fitting. This replaces the original fitting and cuts new threads into the carburetor float bowl inlet orifice. Installed properly, it works well. You have to be very careful to get the fitting in "straight-and-true" and go very slowly. One problem which can occur for a field fix like I did is that chips from the self-tapping can get into the carb and interfere with the needle and seat.

Another type of repair fitting is type that has an o-ring that simply presses into the inlet orifice. This fitting is retained by a screw which is installed through a hole drilled into the side of the carb's inlet fitting body.

The best repair methodology is to have the float bowl inlet fitting repaired by the installation of a Heli-Coil. This is what I ultimately had done for the carb that stranded me, since that was the original carb for the car. It's stored away now, though. Professional carb rebuilders usually have the Heli-Coil kit and experience to do this repair.

[John H.]

Re: C3 1969 carb gasket

One other word of caution. My 72 carb leaked at line fitting. So I thought I
would just snug up the fitting on the line by slightly tightening it.
Well the 90 degree bend in the fuel line looks real cute with it's new
kink in it. Use two wrenches. I learned the stupid way....Big John

[Jimmy B.]

Re: C3 1969 carb gasket

Thanks for setting me straight on the gaskets. I am taking my carb to a rebuilder here that is well known in area for their outstanding work. I was there once and they showed me their state of the art flow machine that they now use. In the "old" days they had 8 engines lined in a row (all the exhaust piping is still in place) where they tested each carburetor that they did before shipping it out. They tell me they do lots of quadrajets as apparently they have many marine applications.

[Joe L.]

Re: C3 1969 carb gasket

Jimmy-----

If you want the carb to live a long and happy life, make sure you plug the holes at the ends of the "heat slot" on the manifold's carb flange. On the car, you can use drive plugs (like miniature freeze plugs and available at most auto parts stores). With the manifold off the car you can either use these plugs or tap the holes for pipe plugs.