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A thermoquad off my 74 Duster 360 #897743
01/06/11 01:59 PM
01/06/11 01:59 PM
Joined: Apr 2005
Posts: 1,489
west kentucky
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gomangoRTSE Offline OP
pro stock
gomangoRTSE  Offline OP
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Joined: Apr 2005
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west kentucky
I have had this carb since the car was in the fall of 1973. My father in law was/is an exceptional mechanic and he rebuilt the carb to really get up and go. This carb had absolutely no bog, or hesitation at all. It was quite the performer. Its been in storage for decades.

My question is: Im building at 440 that is .060 over and has a camshaft with an operating range of 1800 to 5200 range. I will running a 3:55 rear end ratio and the engine will be approx 10:1 and running a modest 450Hp range. I dont remember the CFM rating of this particular carb but I imagine around the 800cfm area. Will this carb work for this combination. I know there are Thermoquad lovers and haters out there, but this carb (which he will again need to rebuild) was fantastic all thru the RPM range. I fan a 4:10 rear end back in the day, and I can afford to buy and use whatever carb I want. I just had always the best performance out this unit.

Re: A thermoquad off my 74 Duster 360 [Re: gomangoRTSE] #897744
01/06/11 02:04 PM
01/06/11 02:04 PM
Joined: Jan 2003
Posts: 75,095
A Banana Republic near you.
JohnRR Offline
I Win
JohnRR  Offline
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Joined: Jan 2003
Posts: 75,095
A Banana Republic near you.
Yes it's an 800 cfm carb and would only need a jet check/change to work on the 440 , place to start would be to compare the 340 jetting to a 440 that year and go from there .

Re: A thermoquad off my 74 Duster 360 [Re: JohnRR] #897745
01/06/11 02:55 PM
01/06/11 02:55 PM
Joined: Sep 2004
Posts: 6,906
IL, Aurora
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ademon Offline
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ademon  Offline
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Posts: 6,906
IL, Aurora
there are some jets on Ebay like 101 pri/ 148 sec or so that you can buy to jet up or you can use a lathe to drill out your existing jets a couple sizes up. I would guess it would need to be fattened just a bit

Re: A thermoquad off my 74 Duster 360 [Re: ademon] #897746
01/06/11 03:12 PM
01/06/11 03:12 PM
Joined: Jan 2003
Posts: 5,270
Missouri
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MY340 Offline
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MY340  Offline
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Posts: 5,270
Missouri
1974 360 TQ's were actually the same cfm as the 400 and 440 carbs. They were rated at 850cfm by Carter with 1-1/2" primaries instead of the smaller 800 cfm 340 carbs with 1-3/8" primaries.

The carb with some minor tuning will work well on a mild 440.


1970 FE5 Duster 360/904/3.91's SOLD 1973 TB3 SpaceDuster 340/4spd/4.10's SOLD Moparless for now but when the opportunity is right I'll have another one.
Re: A thermoquad off my 74 Duster 360 [Re: MY340] #897747
01/06/11 04:44 PM
01/06/11 04:44 PM
Joined: Oct 2004
Posts: 601
Clintwood VA
johnedod Offline
mopar
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Posts: 601
Clintwood VA
I'm running a tq that according to the numbers is a 73 340 carb on my 440 now. Runs great!


Johnedod
68 Road Runner
71 Road Runner
78 Power Wagon
Re: A thermoquad off my 74 Duster 360 [Re: gomangoRTSE] #897748
01/06/11 08:58 PM
01/06/11 08:58 PM
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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RapidRobert Offline
Circle Track
RapidRobert  Offline
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Posts: 36,041
Lincoln Nebraska
iirc 1&3/8" pri is 800 & 1&1/2" is 850 but I think carb CFM ratings can be a little bit misleading. I think either one would work fine for you and they tend to be problematic so if you have a good one take adv of your good fortune & run it!.


live every 24 hour block of time like it's your last day on earth
Re: A thermoquad off my 74 Duster 360 [Re: RapidRobert] #897749
01/06/11 09:10 PM
01/06/11 09:10 PM
Joined: Jan 2003
Posts: 42,714
Spokane Washington
ScottSmith_Harms Offline
Mr Wizzard
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Posts: 42,714
Spokane Washington
I agree with many of the posts above. My advice would be to run it like it is first. You may find that bigger jets offer more power but it's something that you really can't guess and get right, you'll need to experiment. It's easy to drill out jets, not so easy to go the other way, and sometimes even changing original jets can be a bear,removing them without screwing them up can be challenging at times. My guess is that on a mild 440 your carb will run very well in stock form.


Re: A thermoquad off my 74 Duster 360 [Re: ScottSmith_Harms] #897750
01/07/11 08:34 AM
01/07/11 08:34 AM
Joined: Feb 2003
Posts: 607
NY
old340dog Offline
mopar
old340dog  Offline
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Posts: 607
NY
I've been looking for a aftermarket intake manifold to use with a Thermoquad on my 340. And there isn't much of a selection without having to using spacers etc. (Which I don't want to do because of hood clearance problems). Looks like there is also a problem with trying to use the choke setup on the TQ with a aftermarket intake.
Any ideas or suggestions?


old340dog
Re: A thermoquad off my 74 Duster 360 [Re: old340dog] #897751
01/07/11 01:32 PM
01/07/11 01:32 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
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DaytonaTurbo  Offline
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Posts: 21,318
Manitoba, Canada
You can get a holley street dominator. It will fit the TQ and it setup for the TQ choke. Another good one for a combo like yours would be a used edelbrock ch4b. It's a square bore intake but they cast them with enough meat around the carb pad so you can hog it out for a TQ. But IIRC with that intake you would either have to convert your TQ to manual choke or buy an electric choke conversion from demonsizzler.

Re: A thermoquad off my 74 Duster 360 [Re: DaytonaTurbo] #897752
01/09/11 07:27 PM
01/09/11 07:27 PM
Joined: Apr 2005
Posts: 1,489
west kentucky
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gomangoRTSE Offline OP
pro stock
gomangoRTSE  Offline OP
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Joined: Apr 2005
Posts: 1,489
west kentucky
I was wondering myself about hood clearance with the Thermoquad. I assumed with the Holley Street Dominator there would be no issue, however as with other carbs, I would image there would be clearance issues with the Edelbrock Performer RPM??

Re: A thermoquad off my 74 Duster 360 [Re: gomangoRTSE] #897753
01/09/11 08:07 PM
01/09/11 08:07 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
Too Many Posts
DaytonaTurbo  Offline
Too Many Posts

Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
Quote:

I was wondering myself about hood clearance with the Thermoquad. I assumed with the Holley Street Dominator there would be no issue, however as with other carbs, I would image there would be clearance issues with the Edelbrock Performer RPM??




Even moreso of an issue with the RPM because you'd need to run an adapter plate to use it with the tquad.







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