AVS CARTER vs THERMOQUAD?

[johnyACOSTA]

which one is the better?

[911bear]

in my opinion carter all the way ...... just my own experiances

[Nacho-RT74]

both are Carter LOL...

[Duey]

They're both made by Carter.   AVS is a refined AFB that is slightly spread-bore (although on the 440 was almost square bore 1-7/16" pri, 1-11/66" sec)) while the Thermoquad is a big, spreadbore carb with small 1-1/2" primaries and HUGE 2 1/8" or 2 1/4" secondarys...good mileage if you don't put your foot into it.   Some T-quads had issues around cracks and leaks in the phenolic resin body but I think that was mostly on abused/overheated cars...I do love the whump in the rear you get when the secondaries open up on the T-quad.

Cheers,
Duey

[Ghoste]

The TQ is a little harder to find performance parts for.  The AVS has the advantage of being remade by Eddy.  The Edelbrock ones use a two step rod instead of the AVS original three but that's not a big problem.

[cudaken]

 I am a Holley man my self, but the Thermoquad when working right is hard to beat!

Around 1978 my Holley went bad and I was given a Thremo to use till I got a new Holley. Installed the spacer and dropped on the Thermo. Botton end was so much crisper than the Holley. On a 20 mph roll giver some gas and could get the tires going. Could not do that with the Holley 750.

I rather have a good Thermaquade than a normal afb or avs.

Main reason I like Holley better, boy I hate to say this. But I like the way the Holley's look's better than the Carter's. That and when I had Carter's I was only 18-22 and never knew how to mess with the rod's to change the jetting. Holley where for some reason easyer to me?

Guess I will be finding out how to tune them shortly. My new 440 has dual Edelbrock's sitting on top of the Supercharger. Rather have had 850 Holley's or better yet Barrey Grant's but got such a deal on the Edelbrocks I could not say no.

                         Cuda Ken

[Badbob]

The Edelbrocks are made by Weber. Yeah the TQ is a great carb, small primaries for good mileage and throttle response and a 6 pack like secondary kick if adjusted correctly.

[cudaken]

 Made by webber? Sure look's like a Carter. Is Carter still around or did Webber but them? Boy I am old school. Current 440 is the first engine I have done from nothing sense 1985.

                                                 Cuda Ken know's nothing any more.

[chrisII]

im liking this one, its a ? i would have asked soon enough. i have a carter on the car now, but also have a TQ sitting on the shelf that is a reman that has like 300 miles on it. its a 78 440 carb so im guessing its the big one. plenty big for my 365 so i was thinking about using that one when i swap motors. better mpg if i keep my foot out of it sounds good on paper, dunno if i can do that tho lol

[Ghoste]

Carter went out of business some years back and Webber bought the rights to them.  The carbs are physically made by the Magenti-Marelli (sp?) plant in the southern US someplace.
Hey Chris, do you have a model number on that TQ?

[SirNik73]

I like the sounds of the TQ. I almost had on a while back... but my friend broke it when he tried to rebuild it.... damn plastic.... well... I think I'm gonna try and get another one. the fuel economy "theory" sounds good... but I think I'll have those secondarys open more often then my wallet would like.

[Silver R/T]

theyre crappy, but its my opinion, id run holley product

[70mopar500]

Summit has remanufactured Thermoquad  carbs in stock for 300 bucks. Rich

[ODZKing]

I have an AFB on my 67 (stock) and a TQ on my 73, also stock.
The AFB runs much better than the TQ. Smooth, no hic-ups just runs and runs.
I have never found anyone who can adjust the TQ properly and I have tried everything I could find to read on my part about them to no avail.
I finally one wrench who did a fairly good job with the adjustment and it is OK ... but I still prefer the AFB.  Just my  .
BTW, I get 17-18 MPG with the AFB (383) and 12 with the TQ (400) but then again I didn't buy them for the mileage.

[lloyd3]

Not seeing much love here for the AVS, which was what the original carbs were in the day. In 1968 it was 4428s for the 440 4-speed cars, 4637 (I think) for the autos. I believe '69 cars were AVS as well. The factory Mopar carbs were substantially bigger (more cfm air flow than what was available in the AVS aftermarket) and when healthy (i.e.. new and/or unmolested) they were pretty-much trouble free as I remember it.  

[ODZKing]

Nothing wrong with an AVS. As Duey said , a slightly refined AFB.

[lloyd3]

In the middle/late 1970s, a high school friend of mine picked up a 1973 Fury II from a Pennsylvania State Police auction. That car had the biggest Thermoquad I have ever seen, before or since. I was told it was something like 1100 CFM (which seemed unfeasible) until you heard it in use. That big dark blue beast weighed at least 2 tons (he actually got a hernia removing the drivers door to fix some rust, armored?) but if you pegged the accelerator, that monster carb would just howl and it (combined with a surprisingly stout 440, considering it's accumulated miles at the time) would propel that car with shocking force. I don't even want to remember some to the stupid things we did in that car. Small town cops there never had a chance in their 350 powered Chevys.

[62 Max]

They are both good if working right but the TQ will out perform the AVS .I'v run both on 340 and 440,there is a difference.

[DAY CLONA]

which one is the better?

IMHO from experience the TQ will out perform the AFB/AVS, if you know how to properly set one up, as far as reliability, they all have their quirks, but I will say that having worked "back in the day" in a mechanical/bodyshop career, I rebuilt more AFB/AVS carbs than I care to remember

[Ghoste]

I like the AVS just fine.  I think the AFB had a little broader usage and a few more parts out there for a long time because of that.  It was also the one Edelbrock chose to repop first (because of its simplicity?) so that upped the parts factor again.  By the time they introduced their remake of the AVS the market was saturated with AFB style carbs and parts.

[Sublime/Sixpack]

The AVS is a good carb but I much prefer the Thermoquad. I still run one on a 360. Great driveability and fuel economy on the small primaries then when those huge secondaries open up you know it! Plus the phenolic bowl keeps the fuel in the carb cooler than the all metal AVS.

[Nacho-RT74]

have you noticed how old is this thread? ( talking about resurrection )

the owner of the car and OP, sold his cars LOOOONG time ago ( is a friend of mine locally ), and I bet he doesn't sign in into the board since those days

[DAY CLONA]

have you noticed how old is this thread? ( talking about resurrection )

the owner of the car and OP, sold his cars LOOOONG time ago ( is a friend of mine locally ), and I bet he doesn't sign in into the board since those days

That's OK if the thread was started over 10 years ago, and someone intentionally or accidentally reopened it, it starts new discussion for those new to the hobby, or the subject matter at hand

[70mopar500]

have you noticed how old is this thread? ( talking about resurrection )

the owner of the car and OP, sold his cars LOOOONG time ago ( is a friend of mine locally ), and I bet he doesn't sign in into the board since those days

That's OK if the thread was started over 10 years ago, and someone intentionally or accidentally reopened it, it starts new discussion for those new to the hobby, or the subject matter at hand

I did, I thought it was a good topic and for the Thermoquad guys and to let them know that you can still buy them. Rich

[Nacho-RT74]

agreed, just wanted to notice that LOL

[StockMan]

I've been putting together a Thermoquad that I'm going to try in place of the larger AVS carb on my 68 440 magnum.  The larger AVS performs well but I think I could do better mileage on highway with the thermoquad.  I have a 1973 spread bore intake, does anyone know what should be done to properly decommission the EGR ports?  There are the external ones which I'm assuming could be covered with a plate, but there are also the ports/hole visible inside.  Does anything need to be done with them?  I might be better off just picking up an aluminum intake.  Thanks

[hemi-hampton]

I think the biggest ThermoQuad they made was 1050 cfm & hard to find. LEON.

[daveco]

For the EGR, a block off plate is all that is really required. The open ports inside the manifold can be left as is.

[Nacho-RT74]

locally my car came from factory with EGR intake but not equipped, simply sealed, so don't worry about simply install a block off plate.

Edelbrock sells these intakes too, with simple the caps for it if not to be used

[odcics2]

Keep in mind that the TQ was invented as a way to help cope with rising under hood temps for emission standards. Also, to get more MPG at the bottom end, in normal driving.   Better velocity at the smaller primary nozzles = better torque and drive-ability.

They DO perform well if they aren't warped or jacked around with, as in the secondary air door flops open too fast.
That gives the illusion of rapid accel, when the fact is the car bogs a little than catches up.
Tuning one with the choice of changing jets AND metering rods is beyond a lot of guys without a dyno to actually see results.  Holleys are easier to tune. That is a big advantage for most of us.

A good running TQ is smooth from top to bottom. You should NOT feel the secondary air door open. You should just get firmly planted in your seat!   

[Dino]

I remember when I replaced my 750 Edelbrock with an old TQ. I went throgh the whole tuning process, with the help of many members here, and on my first test drive I felt like a 6 year old I was so giddy! I could not believe how hrd that sucker pulled when those secondaries opened. Cruising on the primaries was super smooth and mileage improved as well.

Unfortunately over time other issues with ignition and fuel supply made the carb drip at idle and at this point the carb's going to need a full rebuild and tune again. I'm not sure if I want to do this again or just get a Street Demon or maybe even a Proform. I'll be going to EFI as soon as I can bt will have to rely on carbs for a little while longer. I'd like it to be my last carb though.

[StockMan]

For the EGR, a block off plate is all that is really required. The open ports inside the manifold can be left as is.

Thanks