Picked up a thermoquad at the Long Beach Swap Meet on Sunday. Showed it to Dave - he ID'd it as a 1000cfm unit. Hate to admit it...but I know next to nothing about the Carter/Thermoquad carbs.ou: Need some help decifering the #'s off of this carb. On the top, towards the back - looks something like this: XX 4 6 - 2146 On the back of the base of the carb, the stampings look like this: 6342 SA 902 4 Measured the primary bore at 1.5" and the sec. at 2.25". Dave also pointed out the angled brass discharge tubes (I believe that's what he said they were) in the secondaries. Overall, the carb looks all complete and with no noticeable problems. Haven't decided whether to keep it for future use....or sell it to someone that needs one now.o No: Who on the board either rebuilds these or knows someone that does(other than Jim Weise...pretty sure he does them)?? Any help or advice is appreciated - Thanks!
Thermoquad help http://www.geocities.com/thermoquads/ This link might help with parts. --------------------------------------------- mac meece
I can rebuild the TQ's .. They are getting hard to get parts for. I don't recognize any of the part numbers you listed . Got a picture of it? It's real easy to id a comp series tq, on the top of the carb on each side is a flat retangular area with a raised edge all the way around where a decal goes. Jim Burek P.A.E. ENTERPRISES
One of my text files list the 6342 as a 1973 400 CID AT California application Seems to be a factory 800-830 CFM model unless someone modified it for more CFM. FYI: To add on the what Jim B. said, The 1000 CFM Comp Series carb has a one ring primary booster. (see image below; this from the link that Mac provided) The 850 CFM Comp Series carb has a two ring primary booster.
Comp. series thermoquads are very easy to ID as Jim said. Decal pads on top of the float areas. Fuel inlet point straight down in the back of the carb which uses a fitting like the Holley bowl. I use Earls fittings for a holley. No vaccum or vent tube to connect to the top of the carb.. Just plain racing carburator with an adjustable linkage. I have two comp. series 1000s. They are both killer. I modify them slightly on the rear air door for 100% opening and have discovered that comp. series jets are numbered by orifice size and not flow rate like production models. Jets do not mix! I drill them with #43 and #34. Makes 89s and 120s. Works great!! I also run 10 pounds fuel pressure and the large pull off with eight holes in the backside and a tight return spring. I modify the front shooter with a tube which runs to the rear air door. I solder a brass washer to copper tubing which holds in perminently to the squirter. Also drill the squiter to .035. There is no holley or Demon 4150 carb on the planet which can run with either one of my 1000s. Having said all this a holley will out 60ft the thermoquad slightly although less mph. Higher stalls will not see this. I have an 850 holley flowed to 1008 cfm milled honed flowed. Thermo beats it by 2 mph in the 1/4. I do believe that a dominator will out run a comp series 1000. Not by much i beat. Good thermoquads: Comp. Series 850, 1000s. Double ring booster in 850. HP RB motor carbs. 8901, 8910s and posible other 89xx. All others are junk. Dont buy them they have BIG air bleeds to prevent tuning and tampering. Way to lean for performance. If you cant find a real compl. series thermoquad in good shape, maybe you should buy a Race Demon 1000 with 1.75 in venturi base dia.. I ran a venturi flow calculation on it and shows a true 975 cfm potential. NOT THE CASE FOR A HOLLEY HP 1000. And a HP 950 cfm carb with only 1.59 dia. is not posible. 880 cfm tops. This is at 1.5" Hg. I think this makes air velosity in the holleys way to high and fuel seperation is a problem. Requires running spacers for peak power. I quess this is why buicks like big bore carburators.
Unfortunately, I mis-quoted Dave!!ou: Hate it when that happens. After he looked at the carb and making mention of the larger 1.5" primaries - he said it was the bigger carb. I 'assumed' he meant the 1000cfm unit, when in fact he probably meant the 850cfm unit. I was told by 2 different guys with the same carb for sale, that they came off from 440's. Bottom line is...mine looks to be an 850cfm carb. Wouldn't this work for a mild-to-medium perf. 455 or even a real healthy 350? After looking at the link in the post above - they can modify this one up to 1040cfm. Anyone ever deal with those guys (Demon Sizzler)?? Jim B. or David A. - You guys both work on these carbs....is this one 'useable' for a perf. carb or what? TIA
