carb replacement suggestions

-

MNmoparman

Member
Joined
Dec 28, 2013
Messages
10
Reaction score
0
Location
Minnesota
i have a 1973 dodge dart with a mildly built 360(bored to 380). I currently have a thermoquad(6-2363), with a cracked main body and a leaky fuel well. i need to replace it and i was wondering what to get. i want a 800 cfm spread bore(like my old one). The two i was looking at were a summit re-manufactured thermoquad, but i dont want to be reposting this thread in 5 years so i was wondering if they are durable and run well. I was also looking at the JET streetmaster quadrajet stage 1. Those are the only 800cfm spread bores i could find. The quadrajet is $80 more, i am 16 and have some money to spend but i dont want to spend all of it so try to keep suggestions under $500. So in short, what carb should i get to replace my old thermoquad?

Thanks
 
lf built and set up properly, the thermoquads can be good carbs, there is a good following for them here.

I would run a thermoquad or Holley spreadbore over a quadrajet.


Try looking into a Holley 6711. It's a 650 mechanical secondary spread bore and is supposed to replace the thermoquad. It's pretty big for a 650. However, it can't be converted to electric choke, only manual....
 
No way in hell does your engine use 850 CFM. It might at 8K RPM. I know, it's vacuum operated and all that, but I promise you you've never flowed 850 with it. Everything I've read about those new little Street Demons is good. Like Tony said, I think I would try one.
 
Why not just fix the thermoquad??

i was originally thinking that but i would need to buy a new body and rebuild kit. Also i dont fully trust myself doing it so i would hire someone to rebuild it for me and by then it would cost quite a bit already. i also talked to a trustworthy source who said they are good carbs but not the best and very prone to break and are very complicated and he suggested i get a new one.

i have been reading up on the demon and it sounds good. i think i might go with that one. if i shouldn't, speak now or forever hold your peace
 
i was originally thinking that but i would need to buy a new body and rebuild kit. Also i dont fully trust myself doing it so i would hire someone to rebuild it for me and by then it would cost quite a bit already. i also talked to a trustworthy source who said they are good carbs but not the best and very prone to break and are very complicated and he suggested i get a new one.

i have been reading up on the demon and it sounds good. i think i might go with that one. if i shouldn't, speak now or forever hold your peace

theres hardly any parts inside of one. a new or used center and rebuild kit is a lot cheaper then a new carb.

they are awesome running carbs when right. very complicated? in what way??
 
In a quick search; http://www.dragtimes.com/parts/Cart...uth-9275S-Dart-Duster-Demon_131136622304.html

Or
http://www.dragtimes.com/parts/Cart...0-Mopar-Dodge-Demon-Duster-_251576774791.html

What are the other numbers stamped on the base left side on the carbs base?
These numbers determine the model number and kit to be used.

A kit source; http://www.carbkitsource.com/carbs/tech/Carter/TQ-index.html

To be completely honest, I would seek another TQ ether built and ready to run or a parts carb and give rebuilding it a shot. There not to hard to do, not complex as I think you have been lead to believe. Any carb to be rebuilt should have strict attention to detail. The TQ's biggest area to lat fine attention to is the linkage rods. They must be correctly measured. Then there are the throttle shafts. They should not be worn.

Give it a shot!
 
I love those old TQs. BTW I once ran a 340 with a 2bbl. Ran great to about 5000 rpm. Actually I had the whole 69-318 top end on it; in a 65 Valiant. Back to the TQs though, if yours was set up nice for your combo, they are hard to beat. I esp like the cruise tunability.And you cant beat the roar they make when theyre working hard. A lifetime ago I had a 74 Dart Sport360 with one. I still remember the sound.
 
thank you for all the help and suggestions, i decided to get the demon(sorry abodyjoe)

hopefully it works well
 
Sorry? Doesn't matter to me that you spent more then ya needed to. It's not my budget taking the hit. :)
 
thank you for all the help and suggestions, i decided to get the demon(sorry abodyjoe)

hopefully it works well


I have a demon 625 on a stock 318 and it works exceptionally well.
Make sure you buy the Mopar throttle linkage adapter, it is kinda a pain to install because you have to take the top of the carb apart to put it on.
 
Summit thermoquad (holley rebuilt) looked like it fell out of a truck at 50 mph. That was my experience when we bought one. Then I had to plead with Summit to return it. It worked like shi# and leaked fuel into the intake.
I bought an 800 avs thunder edelbrock for our 440 and it has worked flawlessly for 5 years. If you want a trouble free bolt on plug and play, I'd get a new edelbrock avs in the cfm that was appropriate for your build.

Rusty can rebuild your TQ for you, I think he does or did rebuilds for people. Might be a more economical option than a new carb.

Oh, I see you got a demon. Well, how about post some pics and feedback on how you like it then?
 
Why 800cfm? That seems high. Is your engine naturally aspirated? There is an equation for figuring max cfm. It's CID x Max rpm / 3456 (12 x 12 x 12 x 2), and that's assuming %100 volumetric efficiency. Using the formula, 380 x 5500 / 3456 = 604.74. So, assuming your engine isn't %100 VE, who not go with a 600CFM? Not trying to change your mind or anything, just curious...
 
Because a 800 CFM spreadbore carb acts differently then A 800 squarebore carb and the TQ is equipped in such a manor that the math above you posted can be thrown Out from a moving train.

The TQ has very small primaries @ 1.38 and 2.25 secondaries that are spring loaded for opening up when you want/need them to. The engine will use what it needs with that set up.

The kid gets it.
 
I don't disagree with you at all, but whether it's a squarebore or spreadbore carb, you absolutely can over carb your engine. The engine will use what it needs with that set up, but it may still be more than it needs. Just sayin. He's already bought it so it's null and void.
 
thank you for all the help and suggestions, i decided to get the demon(sorry abodyjoe)

hopefully it works well

I hope that carb works out for you but would like you to know my experience with trying to install that carb on my 71 Demon 340. My original TQ was leaking gas into the intake and the adjustment sequence seemed intimidating to me with no experience in tuning carbs so I opted for a Street Demon 625 from Jegs. The geometry of the carb linkage simply is not compatible with the stock accelerator cable and kick down linkage on a 340 even with the Mopar stud installed. I sent pictures and requested tech help from Demon carbs and they had no answer. It seems to me that they did no engineering work to make these carbs work with stock Mopar linkage. I do not know why they can"t engineer some kind of adapter kit like Edelbrock has for their carbs. Disappointed I sent the Demon carb back to Jegs and they were very cooperative in giving me a refund. I had the TQ rebuilt and now the car runs very well and I am satisfied.
 
So did you rebuild the carb or who did it?

I hope that carb works out for you but would like you to know my experience with trying to install that carb on my 71 Demon 340. My original TQ was leaking gas into the intake and the adjustment sequence seemed intimidating to me with no experience in tuning carbs so I opted for a Street Demon 625 from Jegs. The geometry of the carb linkage simply is not compatible with the stock accelerator cable and kick down linkage on a 340 even with the Mopar stud installed. I sent pictures and requested tech help from Demon carbs and they had no answer. It seems to me that they did no engineering work to make these carbs work with stock Mopar linkage. I do not know why they can"t engineer some kind of adapter kit like Edelbrock has for their carbs. Disappointed I sent the Demon carb back to Jegs and they were very cooperative in giving me a refund. I had the TQ rebuilt and now the car runs very well and I am satisfied.
 
I hope that carb works out for you but would like you to know my experience with trying to install that carb on my 71 Demon 340. My original TQ was leaking gas into the intake and the adjustment sequence seemed intimidating to me with no experience in tuning carbs so I opted for a Street Demon 625 from Jegs. The geometry of the carb linkage simply is not compatible with the stock accelerator cable and kick down linkage on a 340 even with the Mopar stud installed. I sent pictures and requested tech help from Demon carbs and they had no answer. It seems to me that they did no engineering work to make these carbs work with stock Mopar linkage. I do not know why they can"t engineer some kind of adapter kit like Edelbrock has for their carbs. Disappointed I sent the Demon carb back to Jegs and they were very cooperative in giving me a refund. I had the TQ rebuilt and now the car runs very well and I am satisfied.

It wouldn't work with this mopar adapter ?
 

Attachments

  • image.jpg
    3.4 KB · Views: 212
I had no issues hooking the throttle up in my truck.
It is a manual so no kick down issues.
I am pretty sure a member here davebonds got his kick down to work.
 
-
Back
Top