[Trestleking]

Hi, keep getting carbs that don't match what is in this truck.  Don't see any p/n's on my existing carb....so here's what I got, my old carb has a fuel hard line that screws-in at the firewall side.  Both incorrect carbs I have received have a FRONT fuel feed via a barbed pipe that would accept a rubber hose, latest was Autoline p/n C6144.  Just want a stock replacement carb, any ideas ?   
Thks.

 

[Elwenil]

Carter Thermoquad, a very distinctive carb.

 

[Trestleking]

Thk you for the brand recommendation.  The carb pictured has a front fuel feed, mine has a rear threaded feed, so do I just need to modify my pump-to-carb fuel line to conform to what's on the market .....or maybe my 440 has been modified already over the years and what I have is not stock ??

 

[Elwenil]

No, that is a Carter Thermoquad, the stock carb on a '78 440.  The fuel inlet is on the rear of the carb to the passenger side.  You can see the fuel line in the pic above, running down beside the carb.  The pic is of a small block if you are questioning why the distributor is in the rear.

 

[Trestleking]

Thks, I did notice that distributor back there. 
So where do I go to get the correct 4bbl carb that will fit this 440 ?
AZ & Summit don't seem to have accurate lookup references.

Rich

 

[Elwenil]

Rockauto lists one and NAPA lists several. 

 

[RWG75]

Maybe post up a pic of whats currently under your hood just to make sure we're all on the same page.

Here's the thing about getting a "new in the box" TQ: the company that made them (Carter) was swallowed up by Edlebrock years (decades?) ago so all your going to find is rebuilt stuff. The major problem with that is the part number you order has very little to do with what yer likely to find in the box. The design in hugely tuneable and can run on anything from a bone stock lean burn 318 up to a fairly hairy 440 depending on the rods and jets installed. They also have entirely too many linkages and adjustment points for the average assembly line wage slave to get right. I never heard of one coming out of the box and being ready to run unless it came a big dollar, low volumn TQ specialist.

The most common off the shelf replacement is edlebrock performer which is somewhat of a hybrid of the TQ and AVS carbs. The major hair pulling with them is finding the long ago discontinued bits needed to hook up Mopar style throttle cables and kick down rod. I hear its doable with stuff from  a company called Lokar and some fiddling about but I never tried.

My advise has always been roll up yer sleeves and go bare knuckles with the TQ you have. They're a real steep learning curve to figure out, ridiculously cheap to fix and run absolutely great when you get them dialed in. FWIW: I'm running (4) of them right now.

 

[Elwenil]

The Chrysler throttle bracket is still available from Edelbrock.  Part number 1481 for gold or 1843 for black.

 

[SuperBurban]

Unless you real;ly knows carbs, I would go with the Edlebrock, or There is a company that has come out with an updated version of the thermoquad, that I have heard good things about. The edlebrock will likely require a spreadbore to square bore adapter, and the chrys linkage mentioned above.

If you feel gutsey, you could give a shot at rebuilding the thermoquad, but you really need to get each adjustment right, following the instructions step by step. Not a carb I would recommend for a first time carb rebuild, but it is do able.

Then be sure to send the old thermoquad to me for proper disposal. 

 

[Trestleking]

Thks for all your inputs.  My local NAPA was not able to help, EXCEPT to recommend a carb-rebuilder about 40 miles away - in Oklahoma City.  That sounds promising.  If that pans out, I'll pass on the info.

 

[Elwenil]

Your local NAPA is lazy.  They list them on NAPAOnline.com.

 

[RWG75]

Unless you real;ly knows carbs, I would go with the Edlebrock, or There is a company that has come out with an updated version of the thermoquad, that I have heard good things about. The edlebrock will likely require a spreadbore to square bore adapter, and the chrys linkage mentioned above.

If you feel gutsey, you could give a shot at rebuilding the thermoquad, but you really need to get each adjustment right, following the instructions step by step. Not a carb I would recommend for a first time carb rebuild, but it is do able.

Then be sure to send the old thermoquad to me for proper disposal.

You got a link or a lead for the "new" TQ ?? Ya can't just say something like that and not leave bread crumbs. As I recall, and don't quote me on this, the edlebrock carbs have 2 sets of mounting holes. One set for replacing a holley, one set for replacing a TQ.

I've walked a few guys through doing a TQ as their first carb job. It usually turns in to being their first 4 or 5 carb jobs. It's ugly but mostly nothing you wouldn't end up doing with what comes out of the new rebuilt box.

Are brick / motor carb shops going the way of radiator shops? It is the fuel injection age and like that. I'd be more suspicious than optimistic about this lead. Any 'professional' mechanic I ever met that remembers the TQ absolutely hates them and will give you a ton of horror stories about how much they suck to work on. There's a few of us diehards (aka: old timers) around here that actually like working on them but we know what we're doing.

 

[SuperBurban]

You got a link or a lead for the "new" TQ ?? Ya can't just say something like that and not leave bread crumbs. As I recall, and don't quote me on this, the edlebrock carbs have 2 sets of mounting holes. One set for replacing a holley, one set for replacing a TQ.

Its been discussed here several times. I have no experience with it to say one way or the other.

https://www.hotrod.com/articles/inside-the-new-street-demon-750-cfm-carburetor/

I've walked a few guys through doing a TQ as their first carb job. It usually turns in to being their first 4 or 5 carb jobs. It's ugly but mostly nothing you wouldn't end up doing with what comes out of the new rebuilt box.

Are brick / motor carb shops going the way of radiator shops? It is the fuel injection age and like that. I'd be more suspicious than optimistic about this lead. Any 'professional' mechanic I ever met that remembers the TQ absolutely hates them and will give you a ton of horror stories about how much they suck to work on. There's a few of us diehards (aka: old timers) around here that actually like working on them but we know what we're doing.

So what are you saying, should he rebuild his, or not? Like I said, it is doable for a first timer, but chances are it will take some fiddling to get it right. Its what makes the TQ so loved by many of us, that also makes it so hated by others. Total adjust ability, but that also means easy to mess up if you just start trying to tweak, without knowing what the adjustment is for.

 

[RWG75]

That looks very TQ inspired - especially the pic of the underside of the bowl cover. Only design tweak that really gets my attention is the secondary air door adjustment. Looks like Mopar style throttle and kick down connections are still troublesome and I never liked electric chokes. see also: old timer.

I always advocate rebuilding a TQ but I'm also a cheap bastard. It's maybe $25 to regasket, clean the crap out and put a new accel pump in. In the case of cracked bowls, worn throttle shafts or other major fails, there's always dirt cheap basket case donors on the bay. At least worth a shot before coughing up $400 for the carb, how ever much for the Lokar stuff and spending the time it takes to adapt the linkages.

 

[Trestleking]

Ok, more info.  I took some pictures of the carb on & off of the engine.  After knocking off the mud wasp nests it shows to be a Carter T/Q 6-2643.  If this helps anyone suggest at a good bolt-in replacement, great !  If not, I'll be taking it to the rebuilder this week.  Thks again.

 

[SuperBurban]

You have a zip tie holding the secondary air valve open, (The red x). Have you tried cutting it?

Also, the two circled springs are wrong, but that is something for down the road, it would not affect the idle, or driving.

The part number for the carb, is stamped on the bottom plate, near one of the mounting bolt holes.

Here is a good read. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjgmti4xMXcAhULKqwKHfT4A-wQ5TV6BAgBEAs&url=http%3A%2F%2Fwww.retrorarities.com%2Fimages%2FCarterThermoquadInformation.pdf&psig=AOvVaw2DLobE2mIpDUmScCx7tbsY&ust=1532995112319709

Did you have it driving? Right now, I think the zip tied secondary door is the main problem.

 

[RWG75]

I think the problem with that zip tie is more about how its holding the choke partially shut rather than how it's keeping the secondary air door open. I also notice that it has no low idle speed screw (or even a drilled hole for one) and no primary idle mix screws. Add in the choke pull off cover on the passenger side of the air horn and that is not a carb I'd try putting on a 78. I'm thinking maybe a late lean burn from a 318 that some PO swapped in.

This is one of my fave TQ Docs:
https://carbkitsource.com/tech/Carter/pages/tqguide-Vaanth.html

 

[Trestleking]

No clue on the ziptie, this is how my wife bought it off eBay before we were married.  I did drive it last summer, just to fuel up and it was unimpressive.  Need to get a working carb on it, and then the front wheel bearings are next -they are horrible.
    Someone asked about ethanol gas. We have a choice here in Oklahoma and for 15 cents more we always opt for the 100% real gas for everything we have.

 

[Mr onetwo]

Just buy a new Street Demon and be done with it...you won't be sorry