A Thermoquad?

[coupe]

I recently found your discussion forum and am happy I did, there is a wealth of knowledge in numbers! I also had a ball reading the street warrior's forum, took me a while but I enjoyed every race! I have a question for those with carb knowledge. I have a rare (500 made) 1972 "Chrysler by Chrysler" Hardtop, an australian-designed and built mopar with an LA360 in it. The motor is out 60 thou other than that is stock. Originally it had 2BBL but the previous owner put a 4BBL 340 manifold to suit a thermoquad on with an adapter and 650 v/sec holley. I want to change the carb to a carter. The current setup creates untold induction noise and I also like the idea of carters better than holleys, from what I have read.

Am I better to get an AFB (if so what size?)and an adapter or better to get hold of a thermoquad? (I like this idea better!) Can I still get them new or does anyone know where I can source a good rebuilt one? I can get it back from the US with a mate who is coming home soon. For interest, I was told Chrysler Australia only imported 40 thermoquad 340's and put them in some of the E55 spec australian chargers, a completely different car to the one you all know! See www.chargerclubofwa.asn.au for more!

[This message has been edited by coupe (edited December 27, 1999).]

[This message has been edited by coupe (edited December 27, 1999).]

[Thunderstruck]

I am running the Edelbrock Performer carb on my 4bbl 318. It has the spreadbore (Thermoquad style) intake and I can bolt the Edelbrock (AFB clone) to it without an adapter. Finding a new Thermoquad is tough, I've seen them on Ebay and they've bid up to around $200 or so before I dropped out. Getting a good reman can be a trick too. Too many US reman companies just slap carbs together with whatever jets are handy, not to mention Thermoquads tend to leak once rebuilt. I'd buy a new Edelbrock or the Carter equivalent and bolt it to the spreadbore intake, I think you'll also need the Chrysler throttle linkage adapter for this carb.

Steve

[PRO]

I agree w/Thunderstruck,Edelbrock or Carter and depending how hot your motor is I'd favor the 750cfm(Carter #9755),but if pure stock I'd run the 600(#1405) Edelbrock or 625 Carter(#9636)....PRO.... Hey thats a very cool website you listed and the pictures of the 6 cyl. 265 hemi six-pac are too cool!!!I guess these Australian Chargers are actually an A-Body to those of us here in the states,do most A-body suspension pieces interchange? or are they their own breed?.....PRO....

[This message has been edited by PRO (edited December 27, 1999).]

[coupe]

Yes, Sir, Australian Chryslers are based on your A-bodies, in fact the VF and VG are virtually a rebadged Dart. Later ones were based on similar chassis but unique bodies, all suspension parts will swap.
I managed to get on to a guy that will rebuild a Thermoquad in Seattle, WA for $250US. The mopar club up there put me onto him. Since you guys don't think it is such a good thing I will drop the idea.
Thank you for the advice, take a look at a page devoted to my Mopar, The CH Chrysler Hardtop. http://fdnet.com.au/herman/hardtops.html Mine is identical to the top one.
Wal.

[RunnerDave]

I think it all depends on the guy rebuilding the thermoquads if they are a good choice or not.I run a 850 on my car and have 7 buddies running them on their mopars and they kick the s**t out of the holley's we used to use. I'm up in Canada so my builder's name won't help you since he works out of his garage, but don't necessarily write off this seattle connection, if done right those carbs can really put out for you. Just a thought

[440trk]

The Thermoquad IS a Carter. They are GREAT carbs, once set up properly. Personally, I would rebuild it and find a proper intake manifold (if your manifold isn't for the spreadbore style)...
Just my .02

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[goldduster]

Get a thermoquad (T/Q) the pre '75's are 900cfm and the lake ('76+) are 750cfm. around here they are 50bucks+$25 carb rebuild kit. Mopar Muscle made a 360 w/ a T/Q that made 390hp and only cost $2500


GOLDDUSTER

[billy taylor]

i have a 70s 1000 T/Q race carb with no choke rebuild kid cost 12 bucks.it will wake a 340 up.i have many T/Q carbs

[440trk]

Actually, Thermoquads were available in 800cfm and 850cfm since their introduction. The 1000cfm was available "over the counter" from Mopar. I would suggest you try to locate either a Thermoquad from a truck or an earlier car Thermoquad. Avoid any Thermoquad from a "LEAN BURN" application, as they have no "ported vacuum" port for your distributor's vacuum advance.
Good Luck!


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Mike (440trk)

[Toddler]

I have a few stupid questions for you folks
1, What do mean by a lean burn TQ?
2, Would a TQ out of a 80 or 81 Cordoba RS with a 360 work on a 78 360 in a powerwagon 4x4?
3, how would I get around the lean burn problems if I do install the TQ?
Any thoughts would be appreciated

Thanks

Toddler

[cruzerjd]

Lean Burn was a system that Mpther Mopar used in the late 70's to mid 80's that was supposed to use a computer to control various functions of the ignition and engine to adjust the ignition for the best emission levels. Unfortunately, most of these computers were placed on the side of the air cleaner housing where they were subjected to high temperatures and vibration which would cause the computer to fall apart. Also the cars could not be tuned easily because any attempt to change the timing was countered by the computer. Also there was no vacuum advance as the computer advanced the timing as it felt it was needed. Therefore a lean burn tq does not have a vacuum port for the distributor. As for a Cordoba carb, I would pass on it because it is probably Lean Burn equipped. Look for a tq off of a truck or van if that is what you want. So in my opinion stay away from the Lean Burn stuff. It was a decent idea that was applied wrong. cruzerjd

[Diplomat360]

I'd say do not throw away that Lean Burn TQ quite yet. It is fairly easy to drill a ported vacum source in the base of the carb. Other then additional changes to the jetting of the carb itself, and the setup of an idle speed screw on the driver's side you pretty much have a good carb to work with.

I've done this with a few pieces as they are rather difficult to come by and have had pretty good luck.

[azazello]

I had a TQ on the 400 in my 76 Cordoba with lean burn. I replaced the lean burn computer with the orange box kit and vac. distributor and saw some improvement. However, the real wake up came when I threw that thermoquad in the dumpster and bolted on a Holley 650cfm spreadbore (PN: 0-80555S). The car runs like never before, even when it was brand new it never ran like this. I had that TQ rebuilt 3 times and I rebuilt it 2 times myself. It was a piece of junk and I would definitely avoid Lean Burn TQs. I still say if you pick the right Holley for your application (be realistic) you will be very happy. Good luck.

[Ply360dust]

I think sticking with the tq is a good idea
the rebuild kits are cheap and the tq is a very good carb.

the modification for the vac port to disable the lean burn is easy and works well. Check
the main body for cracks and the top (use a magnifying glass) Check out Mopar Muscles article on tq's it shows how to do the mod.
also get a book on carter carbs (summit has it in stock)

hope this helps .

[Dave]

I've heard that the 'trick' to getting a TQ to make HP is in the secondary air door (SAD) adjustment. As the TQ has no secondary booster venturi, they use the secondary air door and the divider plate inside the secondary throttle bore, to pull in and atomize the fuel. Apparantly the amount that the SAD is open, is critical for the venturi effect to take place. Experiment, once you have the jetting right, and see.
The one I run works great!!

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