Rebuilding a quadrajet is an art. There were a few aftermarket parts that helped when we did them daily in the 70s.
We replaced the plastic floats with metal ones. Any scratch on the plastic ones and they will sink over time. It was too risky even using even new plastic floats. One customer return and profits disappear quickly.
We did not replace the plugs back then, but bought special rubber plugs that went in the cavities of the base that would seal these plug areas externally. Winter during the mid 70s prompted a lot or carb repairs of all kinds with leaking plugs. Water somehow got into the gas and froze. During the gas shortage and rising prices days. Many states allowed a small percentage of water in the gas for "condensation". I had a night job and saw water hoses filling in the condensation at some cheap gas stations back then.
Another way to fix the leaky plugs is to remove the plugs, tap and use a pipe plug. See this writeup on Steves Nova Site. Takes a lot of care removing the old plugs, tapping etc.
Also you had to check bowl area for leaks after a dip in the cleaner. Vast Majority were OK, a few had porosity problems in the walls. This was when the cleaner was concentrated enough to do the job in 10 minutes.
Another cause of trouble was over-torquing the air cleaner screw. Which can warp the top of the carb.
We replaced the air adjusting screws also. To repair any damage to the adjuster tips caused by previous adjustments. Which was common in the 70s with many owner-being-mechanic types. Also the replacements had a screw driver friendly head.
Always fun to test one on a big motor and hear the secondaries open up.
Happy Motoring, VHubbard. Nov 2015Back to the 66' Nova page