Carter Thermoquads ~ 'More General Information'

Years ago, I obtained many of these pre-'75 TQ carbs, including 8-10 of the early 4846/4847 CS series, and the later CS. I'd generally avoid the later model CS series made after 1974. If you can get the early CS series from 1969-72, they are the best for all out performance. Many have seen hard use and may be somewhat worn, damaged. Jets for them are hard to find, and pricey- but I managed to find enough years ago to have a personal supply. At the time the Buick GS guys had most of them- and were parting with their carbs, parts, jets to upgrade to Demons, Holley HP, XP, etc.- because carb technology jumped ahead quite a bit after 2000. So I'd get all that stuff with their carbs. According to the GS guys, the 1000 cfm worked, because it slowed down the velocity, allowing the mixture to turn the sharp corners of the flat workbench-like Buick factory intake manifold, thereby getting more into the engine, and making more power.
My own best list is any pre-'75 TQ---with the CA California Emissions, export carbs, idle enrichment carbs as a last resort. Having said that you can de-emission those as well with some extra work, but it may involve drilling out/replacing idle feed holes, air bleeds. So I'd stick with the others for simplicity, and go with the 1-1/2" primaries for 50cfm more capacity, only use the 1-3/8" primaries for smaller engines below 350cid, if at all. The smaller double venturi will tend to nozzle drizzle with a big cam at idle, because it has so much velocity. I've drilled the early CS carb for more idle bypass air with a big cam.
The early pressed jet carbs can be used, but if you pull the original jets, you'll have to work at resealing them with O-rings, sealer, or tap the holes for screw in jets- and risk damaging the jets or carb trying to pull the jets out. The carb lid must be carefully lightly heated, or boiled in water, to remove them if stuck fast. and/or soaked in penetrating oil. If you obtain a number of early CS jets, and they are multiples of the same size, you can drill them for in between sizes using a drill index. There's nothing wrong with a Marine or IH truck carb, they often have rich metering for lugging loads, and work good for performance cars as well.