In their day the Carter ThermoQuad was their equivilant to the Rochester QuadraJet In principle. The bakelite fuel bowl on the TQ is sort of fragile, subject to stripped threads and it sounds like in your case, possibly a cracked fuel bowl.
I believe the TQ was rated at 850 CFM @ 1.5" pressure drop. The nice thing about the design is small primary bores for high mixture velocity and great low end fuel distribution while offering huge secondary bores with an adjustable air valve. The problem with TQs is the lack of real tuning components...jets and metering rods. I believe a possible source for parts, both rebuilding and tuning, may be the Carb Shop, which if I remember is in Chicago or possibly a suburb of St Louis. Try Google-ing Carter ThermoQuad carburetors. Most guys just replace them with Edlebrock or Holley equals but the TQ has a spread bore mounting configuration, which will require replacing the manifold. If you are building or keeping an original car, only a TQ will suffice.
Do not be afraid of rebuilding it yourself....there is nothing scary or intimadating about a carb.....everybody (or almost everybody) has a next door neighbor, whose brother-in-law's cousins neighbor who has a friend that is a carb "expert" who knows all about carbs, except how they actually work. You'll be OK...there a lot guys on this forum that are ready and willing to help. PM me if you want and we can communicate.....and I'll try and walk you thru a rebuild or answer questions.
Cheers,
RJRenton
