Any reason that you are running an old T-Quad ? There are much more tunable carbs available today. Mopar used the AVS back in the early 70's. T-Quads later for emissions. Great carb in its day, but limited in parts and tech info today. The T-Quad carb number for your app I believe was the #4738 . 440, non egr, a/t non-Calif.
The TQ was first developed as a racing carburetor and adapted for street useage later. There is almost no reason to discard this carb in favor of a square bore carb in most applications. The problem with TQ’s is lack of tuning parts, full understanding and tune ability with most people because of the lack of jets and rods. The spreadbore design is a plus and minus. The squarebore is normally an equal 4 way distribution of air and fuel while the TQ has the small and large sides. This also makes single plane intakes for the speeadbore more difficult to have a good fuel distribution which is not ideal in squarebore intakes ether even after pro porting.
I still contend the TQ as an excellent street & street strip carb.
Once you learn this carb you will be very happy with it.
Like all Carter carbs, the rod and jet combos are difficult to get the hang off. It truly sucks taking the top of the carb off to change jets. Adding in the complexity of the rods multiple diameters and how much or little a rod can do for a tune.
Tuning my new 440/thermoquad 850 and have a few questions:
1. My air/fuel ratio at idle is about 16 and the adjustment screws out about 4 full turns out. Sound right?
2. I blocked off the heat risers. Does that mean I can’t use the choke thermostat on the stock intake? If I can, what is the wire for and where do I get power from (or is it ground)?
3. When I flick the throttle the end of the rpms (about 1000 rpm down to norm) take a while to come back down. Thoughts?
What is the TQ carbs number. This can be a huge issue. Earlier the carb is the better unless it is the first year of the TQ. It meters the air and fuel differently.
1: I’m betting you have a a/f gauge since you stated a a/f number so, to go on from there, correct the idle a/f ratio first and as said above, the idle screws should not need more than a total of 3 turns out, which is a lot and still pointing towards the jetting being lean. Which maybe a necessary (or the reverse being rich) evil due to lack of rods and jets available to you at this moment.
2: Blocking of the heat to the intake basically renders the heat riser & choke useless. The electric wire is an emissions part designed to speed up the heating of the choke element to reduce emissions as per the Fed’s. Pictures above is the part you can use to help the choke to operate. How well it operates is a mystery to me.
3: The throttle flicking is the engine/carb out of balance trying to find where it should be. I believe it is a condition of to rich and/or the engines vacuum ripping fuel out keeping the rpm’s up when the throttle is closed. I’m not totally sure. This is a occasional problem for me. Tune the carb and it will come back the way it should. In tuning the carb, make sure you also tune the distributor. When I keep messing around with it, it normally goes away.