Thermoquad cfm on 340

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demondaddy

demondaddy

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I've been thinking about replacing the demon carb on my 340 and going back to A thermoquad. Most of the ones I find are 800 cfm. Are these the ones that came with 340,s or were there smaller versions. I realize they have a small primary and large secondary (spreadbore) does this account for the large cfm? Thanks.
 
Here is a little info on the TQ.....

http://www.moparmusclemagazine.com/...0501_tuning_the_carter_thermoquad_carburetor/

I have very little experience with the TQ, but with the air door adjustment, any size is workable as they really are a variable cfm carb.

The main reason I posted is out of personal curiosity about what intake you're running, what Demon, and if there is a particular issue leading to your thoughts for making a change?

There are some good experienced TQ guys here, one being "RustyRatRod". Hopefully they will chime in as I would like to learn about these carbs also.
 
Awesome questions and right to my point, thank you. I am running A mighty demon 650 cfm dual feed on a edelbrock performer spreadbore manifold with an adaptor. I've been wanting to replace the intake with a performer rpm, but either way i think it,s getting too much fuel. I live and cruise at 7000' plus elevation, if you have any experience with this there is just less oxygen. I thought it might be simpler to go with A small primary spreadbore carb and keep my intake. Thanks.
 
Oh yea, I am driving a 72 demon with A 1970 340, mostly stock, the cam is a little bumpy but i've never had it apart.
 
Some TQ's had an altitude compensator hanging off the front, looked like a little can next to the nipple. might be right up your alley.
 
That actual rated CFM doesn't matter too much, because the air valve controls it. You could tighten it up and run it on a 318. In fact, Ma did so.
 
They were going to run one on the ball stud hemi if it ever made it to production.
 
OldmanRick said:
Here is a little info on the TQ.....

http://www.moparmusclemagazine.com/...0501_tuning_the_carter_thermoquad_carburetor/

I have very little experience with the TQ, but with the air door adjustment, any size is workable as they really are a variable cfm carb.

The main reason I posted is out of personal curiosity about what intake you're running, what Demon, and if there is a particular issue leading to your thoughts for making a change?

There are some good experienced TQ guys here, one being "RustyRatRod". Hopefully they will chime in as I would like to learn about these carbs also.
Click to expand...

Great article Rick! Wish I hadda read that before I rebuilt mine.
 
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