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I stumbled across this forum while researching carter thermoquads, one of which i have on my 1982 dodge b250 with a 318 engine. The carby seems to be leaking alot and running poorly. I want to buy a new one as I'm traveling the states in it and dont have the tools to do a referb. I have looked online but cant find one with the same numbers, do I have to get the same one?
 

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For a street/strip carb, the TQ is THE best carb ever made. The Ford Aust versions used 1 3/8" primaries & are 800 cfm. Cfm is varied by sec throttle WOT position & air valve position. I have inspected lots of Ford TQs over the years, all were set up for close to max airflow, so I don't know where 600 cfm comes from....The 850 cfm TQs have larger primaries, 1 1/2". Chrysler used these on 360 engines, so very versatile. TQs were also used on Inter Trucks & BB Fords in the US. The QJ is rated at 50 cfm less; if you look at the QJ secondaries, it is more restrictive & I suspect that is where the flow difference comes from.
Carter also made Competition Series TQs, in 850 & 1000 cfm. Only made for a few years, now hard to find & expensive. I am lucky enough to own two of them. [ Not to be confused with the 9800 series ]
Carter looked at the QJ & said how can we make a good idea better...& they did! Two float bowls, no leaking plugs, easier adjustments. Many people erroneously think the phenolic centre section was done to save money. Nope, it keeps the fuel 20* F cooler. Less loss to evaporation etc.
The TQs fitted locally were right at the end of the carb era & were jetted increeeeeeeedibly lean. I ran one on my Dodge 440 & it just stopped in 2nd gear. Went home, drilled out the secondaries, & presto, instant performance increase. Some Ford TQs came with 098 sec jets, smaller than the primaries!!! In comparison, Chrys TQs often came with 137 or 143 sec jets. One of the reasons for the small Ford sec jets [ apart from killing performance ] is they use a smaller air bleed.
If you have a Ford TQ, drill the sec jets to 0.125" [ 1/8" ]....& hang on!
Holley have copied the TQ, calling it the Street Demon. [ Hmm, didn't copy the Edelbrock! ] Poorly made & designed, not as good as the TQ. If you want performance, use the TQ.
Carter/Edel AFB/AVS cars are also excellent.
If you want poor throttle response & you want to help Caltex's profits, fit a Holley....
 

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Does anyone know what cfm the carter thermoquad is rated too? I hear that there is things you can do to it to really get it cranking.
I'm getting to be an old guy so don't try to hold me to exact dates. First and foremost the Thermoquads first came out as a race carburetor about 2-3 years before they were ever a production carbs for Chrysler. The first two offered were 850 cfm and 1000 cfm. I bought mine in 1970 and bought a pair of the 1000 cfm versions. The ones I bought had brass floats and screw in jets. They made a track kit that came with different jets and metering rods. The Thermoquads had been out several years before I purchased mine and although I have never worked on any of the originals that had pressed in jets with an O'ring on it that's what the first ones used. I have let mine sit for over five years pulled the tunnel ram down from the rafters bolted it on my car let the electric fuel pump run and initially it would not squirt gas. Mine came with a leather accelerator pump and after sitting for about five minutes and the leather softened it began working just like new. ( Try that with a Holley ) turned the motor over hit the ignition switch and fired right up and ran like a top! I have ran the 1000 cfm carb on motors as small as a 327 small block Chevrolet with stock 3.31 gears with absolutely no hint of being over carbed! With the combination of an adjustable spring on the upper secondary butterflies if the engine is not pulling enough vacuum to overcome the spring the lower butterfly may be open put you will not have any additional airflow or fuel until the motor finally gets to an rpm and vacuum level that will overcome the spring and allow the upper butterfly to open. Even at that with a very small motor it may only partially open. Of course you can loosen the spring and make it open and create a bog but bottom line is they are simple to adjust and very easy to change primary metering on. Just loosen a screw and pivot a plate and the primary metering rods pop up and you can change them and put them back in literally a couple minutes without spilling a drop of gas. As someone else mentioned as I read through some of the forum there are no holes in the bowl area of the carbs and other than a sticking needle and seat or float set wrong you will never see one leak gas. Someone also mentioned a problem with the phenolic resin bowls warping but in my over 50 years of using them racing them and street driving its something I have never seen or heard of from any of my friends that ran them. With 10 screws holding they things together and no reason to tighten any screws more than snug ( again because they don't leak ) the only way I could see them warping would be if they were tightened down on a warped surface or stacks of uneven gaskets. So long as they are flat and put on a flat surface I just can't see where this problem would occur or even be possible. That being said there are lot's of things I have never seen before but I do have an open mind so I will never say that it can't happen or it never has, I'm old but not totally naive.
I first ran a pair of these on my 1965 GTO with a 389 on an Offenhauser manifold with homemade adapters. Although Pontiacs ran in their normal running format which is building torque and relatively low rpm's ( usually under 6000 rpm ) I never ran mine like that, not having a lot of money for aftermarket heads and almost none being available in the late 60's I went a different route, I ran aluminum rods and 12 to 1 TRW pistons, with closed chamber 67 heads ( had the 2.11 intakes and bigger exhaust but still had the small combustion chambers back then I had no idea what the compression ratio was but it labored to start when hot until I had a 6 volt starter made for it. ( please keep in mind there were no mini-starters back then.). I twisted this motor 8000 rpm with 5.13 gears and a 4 speed with a 2.88 low in it and ran as fast as 11.80's which made me a local big dog back in the day. It was all accomplished by gear multiplication which made it easier for the motor to move the weight which was 3600 lbs. If I remember correctly I paid a whopping 68.00 dollars each for the brand new Thermoquads and right out of the box the car dropped from 12.3's to 11.8's and the old pair of AFB's that I pulled off were fully adjusted, jetted and as good as I could get them with years of tinkering. Needless to say I loved the Thermoquads. I parked the car in 2008 after going to a Pinks All Out meet in San Antonio and haven't ran the car since that time. What brought on this thread was somebody contacted me about a car show and getting a bunch of old racers together and I went out and put some 21-22 year old C-16 race gas out of a well sealed barrel and pumped it into my bone dry tank. I had to take the holley electric pump apart as the gibbs were rusted in place and I had to disassemble it soak the rotor and gibbs and after getting them out and cleaning them with scotch brite and then reassembled. The pump worked but unfortunately the steel braided fuel line from the manual pump up to my regulator leaked and looked like a soaker hose. Replaced the line, turned the pump on and again had to wait about 15 to 20 minutes for the leather pump seals to soften and sure enough it pumped fuel. I spun the motor over and after the oil pressure started coming up I flipped on the ignition and it came to life. If no one can understand why I love these carbs after reading this they never will. I also like to look at peoples faces when the hood comes off and they are trying to figure out what they are looking at.
I got away from Pontiac motors many years ago and the motor currently in the car is a 468 BBC, again aluminum rods, again twisting it up with low gears 6.14's and a five speed with a 3.20 low gear. I have twisted this motor to 9000 reliably for many years, the trick is in good valve train and springs. Depending on track it run's 10.0's on a good sticky track and 10.20's on a so so track. All motor, no nitrous, or power adders. Still get the same looks out of people when they see the two Thermoquads sitting on top of the tunnel ram. As far as all this talk about 500 cfm Thermoquads and everything in between I'm totally unfamiliar with them, everything I ever saw had the same size secondary butterflies, but they did make two different sized primaries. The 850 of course had the slightly smaller primaries.
It seemed as almost everything I read was from people that really never messed with them but heard storys about them from other people. I firmly believe they are one of the best, simplist, easiest to adjust or tune carbs ever made. I have a Superflow SF-1020 flow bench and a SF-901 Dyno as well as a chassis dyno. I have tuned a lot of stuff for folks and I will not try to blow smoke up anyone's tail and say they are better than the newest Dominators, or H.P. series Holleys, because you can literally put them directly over each runner and tune each individual hole. I only run my old carbs to be different. I had to make adapters for my tunnel ram and try to split the big secondarys over the runners to help with performance and due to the spread bore design It will never flow as evenly as a carb with the same size butterfly sitting over each runner. I have no doubt I could probably drop at least a couple tenths with a pair of well set up dominators! The look on peoples faces and the never having to do anything to them though makes it more than worthwhile for me. Show me any 50 year old Holley that has sat like mine and ran without major work and maybe I might switch before I croak. LOL..... If any one knows where I could find any of the old 850's or 1000 cfm race series carbs I would like to pick up some spare stuff while it still exist.
 
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