I havew aquired a new 900 cfm thermoquad sitting on a shelf for many years . What should I do to this carb . I am guessing new gaskets but what else and where do I find them ? John
900 CFM??? Carter made 800 CFM, 850 CFM, and 1000 CFM TQ's If you found either the competition series 4846 s (850 CFM) or 4847s (1000 CFM) GREAT score! If you found the superquad series 9800, 9801, 9810, or 9811 (all 800 CFM) good score! Most of the others would have been used O.E. on Mopars. The 1971~1974 Mopars have good value to collectors. Most of the 1975 and newer (unless you happen to have the exact original application Mopar, are pretty much useful only for parts), as they were calibrated extremely lean to allow the dirty (from a smog standpoint) Mopar engines to pass emissions. Trying to use one of the 1975 and newer units without major surgery to the carb, on other than the original application, is a good way to acquire engine rebuilding practice. Assuming it is one which you can use, try it. Most of the components used by Carter should still be OK. Kits are available from specialty suppliers should you need them. Jon.
Its a 9800 so its a 800cfm . Man you know these carbs don't you ? I was wondering if I will have to replace any gaskets or floats on this never used carb . I also scored a B4B he bought in 1982
Jets are the nightmare to find too. I will bet that it's factory calibration will work on a 350, but will not be too good with a 455. I would probably peddle it unless you can find some jets to work with. That's a nice one as it should have an electric choke too, right?
Should work very well with a mild street 455. Will need some calibration change for a healthy race-only 455. The smoggy 1975-up Mopar cores are a good source for jets. Also, jets as well as kits are available mail order. Gaskets should all be OK, try it. Be sure to use the flange mounting gasket which came with the TQ rather than the O.E. Buick mounting gasket. Jon.
Hey Jon There was someone I believe in MO that had a ton of TQ stuff. Was that you or do you know who it was?
Jon I,ve got some T/Quad bits and pieces laying around and most of a Carter Strip Kit for these carbs. Personally I think they're great carbs, originally I was running a 850 on my 455 and that's the best it ever ran at the strip. Then I wanted to use a Quadra/Jet and it's been an odyssey since that time. Course I had a Holley 850 DP that was borrowed, last summer and it sure did feel goood!
Could be! :TU: :laugh: :laugh: Dave - the 455 on the street may never need the 850 CFM, but it REALLY likes the 250 on the primary side (vs 200 on the normal 800 CFM Q-Jet). I personally really like the Q-Jet, but it does have some issues. Think of the TQ as being the perfect Q-Jet (plus it comes in larger sizes). Jon.
Jon Think of the T/Quad as being the perfect Q/Jet, You'll probably get some flack for that statement. If the 455 likes the bigger primaries then that is probably why it likes the 850 Holley.
Dave - those that would give flack over that statement would be only from those who are confirmed Q-Jet haters. The square-bores do work well with the larger engines in a race environment, where no low speed work is necessary. This issue may be resolved in a street environment with rear gears, but at the expense of fuel economy. Can you ever recall anyone boasting about fuel economy with an 850 Holley? When one compares carbs (assuming the comparison made be made with comparable sizes); there is not a lot of difference other than the skill of the individual tuner. Holleys have long had a definate advantage in the availability of parts. No question. However, now that Cliff Ruggles has written a really definative book on modification of the Q-Jets, and is offering for sale some really good modification kits; this advantage is no longer quite so formidable. The Q-Jet does have a couple of issues which are difficult to overcome: (A) about 550 HP seems to be a limit on how much fuel can be pushed through one fuel valve in the small bowl. If one is running alcohol, this figure drops significantly, due to the necessity of more alcohol/hp. (B) making any spreadbore corner at high g levels is challanging. The Q-Jet especially with the small bowl. Now look at the TQ as the "perfect" Q-Jet (or spread-bore): (A) two huge bowls for easier fuel flow for monster engines (B) the bowl design is easily adapted to jet baffles, to allow hard cornering (C) the phenol-plastic body gives the benefit of a large spacer (heat) without the low speed velocity problems. The biggest disadvantage of the TQ is the lack of cheap tuning parts. While I could rectify this issue, I am not going to invest in doing so until more individuals see the benefits of using the TQ and create a demand. We make the parts as needed, so they are available; just not cheap. Jon.
I think the biggest advantage of the T/Quad is the price. Since they are unpopular you can usually get them cheap. Last one I picked up was a 850, don't know the year but it has two bowl vents instead of one, got it free just for asking. :Brow:
just to add.....rear hung floats offer an advantage on acceleration I believe. I used to drive my 11.60 GS to the Nats in the early 90s (13 hrs) getting 16 mpg at 65 with just an easy primary metering mod change I was ready to run at the track. Not so easy to change them on a Q-jet! Bruce BQUICK JAGUICK
