What year did leak leaky float bowl bottom plugs end ? 1968?

[GSP7]

Was it 1969 carbs and newer that you didnt have any leaky bottom plug issues anymore?

[ourkid2000]

Cliff's book says this:

"Very early units have brass cup plugs. The leakage rate for these units is almost 100%..........Later units made after about 1968 used pressed-in aluminum plugs. We still see a few of these that leak, but not nearly as often as the early-style brass plugs. The method to install and swage in the aluminum plugs continued to improve through the years of production. It is quite rare to find units made from about 1975 and later that leak".

I hope this helps!

[Cliff Ruggles]

1969 and later units have thicker castings and pressed in rear bottom plugs, so not prone to leaking.  They also started doing a much better job of sealing up the front plugs getting away from lead and going to aluminum.

In any and all cases part of your rebuild should include leak checking bottom plugs BEFORE you make any type of repair.  If you are working on a 1969 or later unit very few will be leaking anyplace.  By 1975 they pretty much had all that sorted out and I have seen very few leaking plugs on any of the later units.

Even so nearly 100 percent of the carburetors I've taken in for rebuilding or restoration have a TON of "monkey chit" smeared over the bottom plugs. This is a very BAD practice as there is very little clearance between the rear bottom plugs and the baseplate.  So the thick layer of epoxy often hold the baseplate away from the main casting.  This can cause a vacuum leak but even worse it may cause the shafts to bind as it puts the baseplate in a slight "twist".  I've removed the epoxy from so many castings to correct those sort of issues I've lost count.

So if you read what I'm putting up here leaking bottom plugs are mostly a myth still regurgitated on nearly every thread or discussion that comes up about Quadrajet carburetors.

I'd also add here, and it's in my book that "dabbing" epoxy over leaking plugs is about as effective as cutting off your arm and putting a band-aid on it!  JB Weld is also USELESS for this purpose.  It will NOT hold back fuel or stay attached to the casting......FWIW.....