and dont forget to flip the stock air cleaner lid over for even more sound,

Thermoquads and Q-jets are like mullets; Business in the front, party in the back!!

I love the sound of a quadrajet when the secondaries open up.

Had one on my 71 Dodge Demon and it always seemed to starve the engine when you stood on the throttle. I was running NHRA stock class so I got in touch with Ed Hamburger at MOPAR and he showed me how to modify the accelerator pump lever and how to get the air valve on the secondary to open all the way. Once I got that sorted out that 340 screamed at wide open throttle. I liked that carb because I never had a fuel percolating problem at the track on a hot day and no vapor locking.

this would make a killer episode of engine masters. Holley vs Edelbrock Performer/AFB vs Edelbrock AVS, vs Q-Jet, vs ThermoQuad vs Predator vs FI tech TBI fuel injection.

Thermo-Quads are not easy to tune but they are great, great carburetors! Smooth idle and smooth ride in low rpms, great torque and incredible top end power! I’ve tried almost everything in my bbc, Holley, Edelbrock, fitech, I really like the Thermo-Quad better, awesome Carburetor!!

AWSOME!! I have 14 thermoquads in the garage. I even have an original 70’s offy spreadbore DUAL CARB for a b block mopar. Love Thermoquads!!!!!! Soon to go on one of my 1979 t top 300

Freiberger, around 1972-73, I ran a 1000 cfm thermoquad on a 283 SBC with an adapter on a Z28 manifold and Z28 solid lifter cam with a 4 speed behind it in a little Chevy II. Worked perfectly. No complaints here.

Such an old video but I have to comment. The thermoquad came in three different CFM ratings. If you're lucky enough to have a first run issue on a 340 that was the 1000cfm Competition Series. The 800-850 was next and it's secondaries are 1 1/2 with the third being the 800s whose secondaries are the smaller 1 3/8. The secondaries are considered vacuum and not mechanical. It must be used on a spreadbore intake and as someone else mentioned WITH the 1/2 spacer as it also displaces heat. Not using the spacer, and placing the TQ directly on the intake, is the primary reason for the phenolic bowl to warp. The other reasons that can cause issues are using a screwdriver to pry the air airhorn off or over tightening of the airhorn's 10 bolts. The main reason why people do NOT like the TQ and may prefer Holley is that they don't take the time to properly adjust the TQ, but when properly adjust will outperform equivalent carburetors of the competitor's if done right. People prefer Holleys and Edeljunk as they are easy to work on but who wants to keep replacing power valves and adjusting float levels at every turn on a Holley or adjusting the A/F on an Edeljunk day in and day out? Take the time to do it right and the TQ will smoke the competition. I have ran a TQ for three years after trying numerous Holley and Eddy carbs and the others are just a time consuming hassle. If you set the TQ properly, you wont have to touch it for a very long time.

Nothing was as cool as the sound you got from flipping the lid on one of these.

My 71 340 dodge demon had one and my MOPAR direct connection dealer had all the good tech info to make them work fantastically.

One of the best videos yet!

For a carburated off roader you cant beat a tq, those sidemount floats keep fuel going while on an incline.

Love these Episodes keep it up guys

Quadrajets and Thermoquads are great carburetors. People only dislike them because they're too dumb to know how they work. Or they rather have the easy carburetors like holleys or edelbrocks. which is understandable. In a hurry on race day, pop the front bowl off your holley, change jets, off ya go. Qjets are set and forget, but they look scary and daunting to the uninformed and are not very user friendly. They only bog if the air doors are too loose. That's it. On qjets there is a little 3/32 allen set screw and a flathead screw. Adjust the tension, drive around, floor it, repeat until bog is gone and carb performs to your liking. Not hard. Also, for you new or old to the world of Qjets, if you have the later hot air/electric choke style (usually '75 and up had em), take the carb apart, punch out that aluminum plug infront of the choke tower, and tap it for a pipe plug. Badda bing badda boom. Instant adjustable part throttle without having to take the damn airhorn off. An AFR gauge helps wonders too. I've seen people get an additional 5mpg from tuning the apt screw alone.

Never knock Q Jets and TQs. Both very efficient for their application being fairly standard engines. Both a pain [dont do it] to modify but generally better than a square bore Holley on a stock engine. I have worked on a 70 Challenger 340 with the TQ and I feel Mopar even used them earlier. Here in Oz Ford used them on 302/351 Clevelands from 76-82. But so lean and such crap cams they burnt out engines. Not the carbs fault just the spec they were made to get those emmissions.

Freiburger is the only person that can say thermoquad in the way it sounds like it should be said

Awesome video Worked on plenty of them in the day. But never knew the facts and history

that was good and straight to the point thanks keep up the good work guy's

David, I been rebuilding Thermo Quads since 1971! Great carb! I have the 750 cfm on my 71 Demon 340 I also have a 1,000 cfm my buddy ran in 1972. Easy to rebuild. My last rebuild was 1985 and still running strong! Love the sound too!❤

Quadrajet carburators are great, plus the sound of them at wide open are even better.

I have rebuilt many Thermoquads. They are good carburetors. Usually, all that was wrong was the 2 thick rubber washers for the main wells would get soft or crack.

I can remember going to the scrap yard and finding one of these on a Dodge and taking it. Loved the "Thermal Quad" idea!! LOL I stuck it on a 318 that I put a 4 barrel intake on. It ran okay and made a great noise...LOL..LOL

74 Plymouth Satellite police package....high performance 360 with the Thermoquad. Secondaries were like toilet bowls. Loved the sound when you put it to the floor.

The sound of a 440 magnum police car (71 and older) is only exceeded by a hemi equipped vehicle with factory exhaust, yes i was around when people were driving factory hot rods just like they left the factory. You had the ford vs chevy vs mopar BUT the elephant (hemi) silenced them all...

always fun to watch you geek out.

Thermoquad+flipped lid + that v air cleaner + salad bowl. Make it happen Freiburger

I feel like Freiburger is a boss at reading prompters or remembering lines because there is no damn way he holds all of this knowledge. I can't even remember what I went to the fridge for half the time and he just spits out knowledge like a audio book.

TQs work very well when set up right. 1 trick is to epoxy the fuel sumps for the main metering pick ups, 1 on each side, to avoid the OE glue from disintegrating and the caps falling off, which leaks raw fuel into the engine, creating a hard start or just a horribly rich mixture. Another is NEVER over tighten the screws that hold the 3 main pieces together, and follow the sequence. You'll warp or even crack the plastic bowl if not. Lastly, rebuild kits are still available, and brass AFB/AVS floats can be made to replace the OE foam floats, BUT, if your TQ is running lean, be sure to check the throttle bushings in the baseplate, both primary and secondary, for vacuum leaks. These are N/A new and if yours are worn out, you need to source some NOS 1s, or find a different baseplate..( this happened to me and I eventually retired the old girl for a 750 AFB) Another thing of note, is when custom tuning your TQ by changing metering rods, please note that there are 2 different length rods! The shorter rods will fit, but will cause massive flooding. Let me hear that WWWaaaaaaahhhhhhhhhhhhhhhhhh!!!

Tune in next week when David explains Betamax video players.

Thermoquad came in 850 and 1000 CFM versions. Hot Rod Magazine did a story on the 69 Buick GS that had a 1000 CFM thermoquad installed as a replacement for the GM 750 CFM Quadrajet that came on the car originally. The car ran at least two seconds quicker in the 1/4 mile. They costed around $85.00 back in the day. I should have bought a few, but never did. Too bad, they would be awesome today!

They remind me a lot of the Pierburg 2E you find on 1980-1990 VWs. A good but very misunderstood and hard to tune carb.

I really like these thermoquads

I love the content. I hate that youtube chooses to play a toyota ad before EVERYTHING motor trend uploads for viewing.

In essence the Carter Thermoquad's secondaries operated somewhat like a constant velocity carburetor found on some motorcycles where demand increases the air/fuel mixture from the carb so that it doesn't overwhelm the engine and cause it to bog like when you put a 850 Holly double pumper on a small stock engine that can't handle it.

Good stuff, this is interesting

That Freiburger is a one take wonder! Turn him on and watch him talk, I could listen all day. #mancrush nohomo

way back in old times when i was a 17 in 1987 i had a modified pontiac 400 in a newer 4 door catalina we called the four door tire fryer that had a spreadbore carb and the tires would chirp when you kissed the secondaries in first gear and if you floored it it would either rip the tires apart or grab and accelerate so hard the dash board would shake and sometime the slide in stereo would slide out, weaker passengers would scream for their lives "omg slow down! ahhhhh"...but now im all efi

my 6.6 TA had a quadratoilet on it. i could see the gas gauge dropping at WOT...yet my 73 merc Capri had the sqaure webber. awesome little car.

The one on my 340 Cuda ripped very well. The 4 spd was a riot.

My favorite carburetor. Back in the early 80s I had a 72 340 Duster that had the thermoquad on it. I think it was a great carburetor and worked well. A lot of people did not understand how to adjust them but I won't up working on thermal quads and quadrajets where most everybody else only knew how to work on and adjust or modify Holleys everyone I knew that had Carter or Rochester carburetors having me work on them for them.

Love some the cars these guys build and the projects and knowledge is vast I was fixing up my car but a few days ago on the 9th I hit ice and wrapped it around the end of a guard rail but somehow managed to walk away with just bruises lol back to the drawling bourd

Have a 1973 dodge challenger daily driver the thermoquad works great every time; well as long as it isn't 110 degrees outside.

I would like David to do a show purely for him explaining some of his best moments through his life and some of his most loved accomplisments.Or write an auto biography.

I had a carter wcfb 4 barrel on my 57 chevy 283. I used to see the mechanics, were I worked, draw filing the fuel bowls to get them to stop leaking(warping) otherwise they worked. my 48 chevy had a Zenith carb(I never did know why but it was original equipment).

For a long time Carter was making more quadrajets than Rochester. I was the first assembly line inspector on the TQ line.

I had a couple of quadrajet carbs, one on my 1970 Transam and one on my 1976 Chevy shortbox pickup, only complaint with them was the piss poor stock filter that would let small debris in between the needle and seat and the carb would flood forcing you to take it apart to clean it, problem was solved with an after market fuel filter plummed in

I had one on a 302 Ford. I turned the air cleaner upside down to let more air into the Carter thermoquad carby

you can adjust the spring tension for the secondary and there were different needles and you can adjust the needle heights very customizable

I like to see a video to compair this with other carbs

That was my most memorable carb!!!

older gentleman always said "you gotta be 3% smarter than what your working with". as long as there is a junkyard and parts house there there are good Carter products.

SMI carburetor sells these carbs "worked over" for your specific application. I switched from a holley to Q jet and it gave me 3 tenths better in the 1/8th. Setting it up and finding a good reman'd one from Autozone was the tricky part,lol.

Did I miss something? Frieburger never said why it "punishes you for going wide open"...

I've got a Quadrajet on my 79 K10 pickup. totally stock 350. hot air choke. Once I actually took 5 minutes to adjust the choke the thing now starts first time every time with just one pump to make sure the choke is set and to splash a little fuel in. The truck always ran pretty decently (i've had it about 2 years now) but it just never started up immediately. All it took was a little adjustment on that choke and done, high idle works well, blip the throttle and it idles right back down like it should. I'm by no means a mechanic so it was a big deal for me to have done that by myself. lol. The truck is just a project/toy. And the last vehicle my father and I both worked on before we lost him to cancer back in January. I need to find something to drop a Thermoquad on. I've got a few vehicles I picked up recently that I could make an attempt with. Would need to put a new intake on the 350 in my station wagon because it's got a crappy 2 barrel intake on it now.

Freiburger you should do an explanation on the 6pack from the molars and the triple duece from the old school GTO

I like them, they have different sizes for different engines. Its best to keep the largest fuel line up close to carb.

So much knowledge in that funny shaped head

Simplest carburetor to rebuild and tune. I could take one from a 440 and place it on a 318. With a little adjustment, it would run great.

How about doing one on TBI FB's . And top replacements.

Thermoquad - The v-tec of the 70's

Closest you can get to fuel injection from a carburetor.

International used them for a few years as well as well.

waaaaooooooooooooo.....my favorite sound from a stock 4 barrel carburetor....

Hey guys, these were fitted to every Cleveland from the XC-XE Falcon's in Australia on both 302 and 351 variation s.bwhaaaarrrrrrr definitely brings back memories haha

In the Eighties my B&M blown '70 Z28 454 had dual Carter AFBs. Never knew AFB meant Aluminum Four Barrel.

I love old motorhomes.

I've got one of these mounted on a 440 in my 1975 Dodge pickup. It's no slouch.

Wish I had this inter web thing, back when I was younger. The knowledge given to us, here, would’ve come in handy, and we all would’ve had some bada$$ cars tooling around our high school. Knowledge like this was only reserved for those in the machine shops. And they weren’t sharing.

Don’t forget the WCFB - Will Carter’s Four Barrel. I believe that’s the one David referenced as the original four barrel. Marketing department knocked it outta the park when they named that one!

Needs more in depth carb videos

Roadkills 75th episode should most definitely be the Battle of the best between Roadkill, roadkill garage, and hot rod garage definately would left to see nascarlo vs 5.0 mg

thanks frei

Does anybody remember the old Predater carb from the '70's? It was one large square bore with a vacuum operated valves like the Q-Jet secondaries and it had the same outside footprint of the square bore Holleys. It was something of a mystery carb that never really caught on.

The TQ was used here in Oz 76-82 on 302 and 351 Clevelands.. Set so lean that they BBQ the valves and seats and guides. Though a then Chrysler Australia employee I know had one on his 327 Chev Holden. And it was quick. The 340 Chargers were never officially released though quite a few got out the back door. A couple in VG 2 door [Dart to the USA] and then VH Charger [A body] The Supercar furore in 72 lost us the 340 Charger, 308 XU1 and Ph4 GTHO Falcon. Blame all Muttering Rotters.

hey i am a thermoquad fan! I am wondering what kind of epoxy you or Dulcich have used to repair the primary jet wells? Thanks...you guys rock!

Don’t forget the 1000cfm race version from the late 70’s

Good God... Did Alana restore a thermoquad? That thing looks new.

Very cool.

You should do a vid on a third gen trans am

My 1974 Grand Prix had a carter quadrajet

SO if I understand correctly, on the secondary side of things... there are the butterflies(?) AND the 'door'. Is that correct? Also, does that 'door' operate on barometric(?) pressure? The more suction the more it opens?

Five vintage Mopars in my yard - two motorhomes (360 and 440), a Newport (400), and a pair of trucks (318 and 360), and they each have a Thermoquad. Why? Cause they work, and the sound is pure Mopar. I love the looks I get when my old motorhome blows the doors off another motorhome and the howl from the TQ rattles the next ride over.

Two Guys Garage on Velocity covered this almost word-for-word back in April. Strangely the episode replayed just this morning. Not claiming plagiarism but it was shockingly identical.

I wonder how it would affect performance on a rotary?

Had one on my '80 Ramcharger with a 360. Near the end of my time with the truck I had to manually jam the choke open to get it to start first thing in the morning. Never did enough troubleshooting to figure out why.

Do thermoquads use the same jets and metering rods as AFB and AVS carbs? Thanks heaps for your informative videos.

I'm looking to replace the Carter Thermoquad 440 Carburetor on a motor home. Which one do you recommend me getting?

So if it bogs down when you gun it how can you tell if it’s not getting enough air to open the back butterfly

My cordoba 400 in my 77 newport has a fully electric carb with a float level sensor and solenoids instead of mixture screws. It is 800 cfm

Ford used Thermoquads in 1974 only California only 460 v8s. Also Ford used Quadrajets on some 429 Cobra jets due to the Autolite 4300 being such a awful carburetor.

AFB and AVS are the way to go, I ran 2 AVS' on a short Offenhauser short 2x4 intake on a 428CJ with a Competition Cams super stock grind cam @ 626-653lift and advertised duration of 304-314 solid lift, not a roller , good old Mallory dual point ignition big Hooker Super Comp.headers , a GER(George E.Rynolds does anyone remember the GER ads in hot rod mag from the 80's or PAW ?) 3600 converter and a Dana 60 with 4.56 gears in a 68 mustang coupe! While I have had faster cars (in the qtr.) I don't think I could ever duplicate the fun that this build created. While you kids today are pretty used to 70+ mph rolling smokey burnouts with your LS turbo cars it was kind of unusual back then. I wonder if you can still get ack issues from the 80's? I would like to buy some or one to document how kids from that time period, went about a build like this, before the internet and Amazon prime shipping! @David Frieburger, let me know if you have any back issues from that period, and I know you remember GER and Performance Automotive Warehouse (PAW) I think that would be a great topic for one of your short videos, Kids these days don't know how good they have it(overnight shipping and street cars that can run the same numbers as pro stock cars from the 80's) And I am sure that the same thing was said about us, by the older guys from the 50's60's and 70's.... Oh yeah, that mustang with the giant cam and 2 fours got worse gas mileage than my wife's V-10 Excursion that gets 7mpg (probably about 4mpg), some how I never really thought about it in the mustang, but am annoyed to no end with the Excursion... Tune in next time for my Rehr, Morrison, Shepard Camaro clone build that followed the mustang!

I had a 79 st.regis cop car with the thermo quad and it flew.

Q jets have their downfalls. Gave one away I tuned with a wideband to run on a street big block. Made 17mpg with an oD transmission. And responded well.

Don't forget that Carter had to help Rochester out making the quadrajunks when they got burdened down.

i love they make parts for their competitors also, carter-weber is a thing.

Yes

+Finnegan's Garage, +Motor Trend Channel, As a true fan it was not you who said "The only carburateur who punishes you for wide open throttle" ... It was Mike, you know the funny one. ;p

Carter Thermoquad and Rochester Quadrajet

Hardtail Honda Z50 on the left!