Carb recommendations for my 340

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My old 85 Ram had a factory roachester lol Q-jet. That truck was a factory slug.
 
Dan the man said:
First off let me say that it's highly possible that I may not have looked in the right place but I didn't find any information on a q jet being used or available for a sbm
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Somewhere around the mid ‘80’s, QJ’s are round a good bit. Exactly when, IDK. But that did become the replacement carb for the TQ at one point.
AJ/FormS said:
I heard
that the QJ on the Mopes was due to a TQ availability crises, back in the day. It sorted itself out soon enough and TQs retook their rightful place.
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I’m not a 100% positive on anything on that topic. What I do know is Carter was making QJ’s for Rochester for a while. I never head of a TQ shortage but I did notice both were available or used at the same time towards the end of Carters run as a biz.

Carter officially folded up in ‘84? IDK for sure. I forget.

From there (or approximately from then on) QJ’s were on top of the MoPars.
 
Bewy said:
QJ is a spreadbore like the TQ. Same bolt pattern. You need to check fitment to the intake to make sure all the passages in the carb base are covered & that linkages do not foul etc....
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My son has an 85 Dodge Truck with a 360 that came from the factory with a QJ. Think QJ's were cheap and Ma Mopar was savin' a few bucko's.
 
rumblefish360 said:
Somewhere around the mid ‘80’s, QJ’s are round a good bit. Exactly when, IDK. But that did become the replacement carb for the TQ at one point.

I’m not a 100% positive on anything on that topic. What I do know is Carter was making QJ’s for Rochester for a while. I never head of a TQ shortage but I did notice both were available or used at the same time towards the end of Carters run as a biz.

Carter officially folded up in ‘84? IDK for sure. I forget.

From there (or approximately from then on) QJ’s were on top of the MoPars.
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I've been out of the car scene for a while now so I don't even know if there's any salvage yards in Missouri like they once were. I did do a little research on spreadbore carburetors and I think that the holley 650 was the only spreadbore carburetor available. Does edelbrock even offer a spreadbore carburetor? Unfortunately I'm not real good with carburetor tunning so I would need one that doesn't need constant tunning. I have done some research on carburetors and from what I've read the spreadbore gives the best throttle response and driveability. You guys have said that the Thermoquad can be tuned for a 318, is that changing of the jets? Sorry I didn't mean to highjack the op thread
 
Ricks70Duster340 said:
My son has an 85 Dodge Truck with a 360 that came from the factory with a QJ. Think QJ's were cheap and Ma Mopar was savin' a few bucko's.
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Up till 1989, all of my vehicles were used, mostly from the 70's so I don't have any idea of what carburetors were available on the mopars. I didn't even know that they have Q-jet on them until today
 
My 81 w150 came from the factory with the 318 and a TQ. I loved that combo. Had 3.21s and I put 32x11.50-15s on it...I also had an 89 diplomat that came with a QJ and I had all kinds of problems with that one til I swapped it out. I originally swapped it for a new, identical factory spec QJ and it took was crap but in different ways. It wasn't til I put a Carterbrock on that car that it started running like I expected.
I didn't have access to a TQ at that time for whatever reason
 
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Dan,
If you can find a TQ.......just run it. I could never work out why a 440 with a TQ [ #6410 ] had .125" sec jets but a #6454 used on a 360 had .143"sec jets.
Jet size is NOT related to engine size.

If you use a TQ on a 318, you may have to change jet sizes &/or met rods. What you will have is great throttle response, mileage & power.
 
Bewy said:
Dan,
If you can find a TQ.......just run it. I could never work out why a 440 with a TQ [ #6410 ] had .125" sec jets but a #6454 used on a 360 had .143"sec jets.
Jet size is NOT related to engine size.

If you use a TQ on a 318, you may have to change jet sizes &/or met rods. What you will have is great throttle response, mileage & power.
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I just did a quick search for a TQ Carburetor and they go anywhere from $400 - almost $2100
 
I'm really surprised that more of you guys didn't mention the tried and true thermoquad. The 340's came from the factory with them, guys have said how easy they are to tune and how much better they are for throttle response and yet the thermoquad was only mentioned a couple of times. A edelbrock performer rpm and a thermoquad carburetor and your good to go. Is this bad choice?
 
Dan the man said:
I'm really surprised that more of you guys didn't mention the tried and true thermoquad. The 340's came from the factory with them, guys have said how easy they are to tune and how much better they are for throttle response and yet the thermoquad was only mentioned a couple of times. A edelbrock performer rpm and a thermoquad carburetor and your good to go. Is this bad choice?
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The big PIA about there use is they have a choke that uses a choke well on the intake which the LD-340 doesn’t have. Rigging up a pull cable is a PIA and IMO, doesn’t look very good.

I used a 440 TW on top of my LD-340 without a cable.

I don’t know where you have seen a TQ for those prices but I’d guess there rebuilt. I have a few for sale as of this date in the for sale section. 1 ready to run and a couple rebuildable that I listed as for parts.


Chevy arm, small primary, electric choke TQ I personally used on top of a B block 400 cid engine. Swapped for a big primary TQ. Removed and drained. Shelved inside.
[FOR SALE] - Electric choke TQ
 
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rumblefish360 said:
Oh man you opened up a can of worms! LMAO.

AJ is right on carb size working from little to big. Considering the build, I’ll also assume a decent gear ratio is back there for the go fast effect.

I can only say what I would do and having used a 600 AFB to a 750, I liked the 750 a little better. Even on the lower rpm side of just around town or initial take off, there was a better and more powerful feel from the gas pedal. Of course, everything will be the state of tune.

If you don’t have a preference of intakes, I would use the RPM. I’ve had both intakes, so there’s that behind my choice. Nether is bad and nether is worth getting rid of for the other. Since you have both, try it for yourself and decide.

Some will run the LD-340 because it’s a ”Day 2” hot rod part and others will run the rpm without care or concern of that period correct hot rod part.

So far my favorite combo was the MP tips modified LD-340 and the big TQ.
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rumblefish360 said:
Oh man you opened up a can of worms! LMAO.

AJ is right on carb size working from little to big. Considering the build, I’ll also assume a decent gear ratio is back there for the go fast effect.

I can only say what I would do and having used a 600 AFB to a 750, I liked the 750 a little better. Even on the lower rpm side of just around town or initial take off, there was a better and more powerful feel from the gas pedal. Of course, everything will be the state of tune.

If you don’t have a preference of intakes, I would use the RPM. I’ve had both intakes, so there’s that behind my choice. Nether is bad and nether is worth getting rid of for the other. Since you have both, try it for yourself and decide.

Some will run the LD-340 because it’s a ”Day 2” hot rod part and others will run the rpm without care or concern of that period correct hot rod part.

So far my favorite combo was the MP tips modified LD-340 and the big T
rumblefish360 said:
Oh man you opened up a can of worms! LMAO.

AJ is right on carb size working from little to big. Considering the build, I’ll also assume a decent gear ratio is back there for the go fast effect.

I can only say what I would do and having used a 600 AFB to a 750, I liked the 750 a little better. Even on the lower rpm side of just around town or initial take off, there was a better and more powerful feel from the gas pedal. Of course, everything will be the state of tune.

If you don’t have a preference of intakes, I would use the RPM. I’ve had both intakes, so there’s that behind my choice. Nether is bad and nether is worth getting rid of for the other. Since you have both, try it for yourself and decide.

Some will run the LD-340 because it’s a ”Day 2” hot rod part and others will run the rpm without care or concern of that period correct hot rod part.

So far my favorite combo was the MP tips modified LD-340 and the big TQ.
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Yeah I should’ve expected a conglomerate of answers it’s kind of like asking people what’s the best cam which is super subjective. And yes it’s going to have a decent gear ratio on it I have a set of 3.91s on the side. And a day 2 build is exactly what I’m looking to do all parts I have for the most part are about mid to late 70s. I just have a major appreciation for people that keep their cars to the time period but of course there’s nothing wrong with taking advantage of modern tech. I want to run the LD but my issue is the plenum divider being completely removed and ported a ton for a race application and I’m not sure if that’ll affect how drivable it is. Also an update on the carb I got a Holley 750 DP from my dad as he’s going to a fitech system for his car. I appreciate everyone’s input thank you
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Dan the man said:
A edelbrock performer rpm and a thermoquad carburetor and your good to go. Is this bad choice?
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performer rpm is a square bore, which means you'd have to run a spacer/adapter. also no choke well. so if you wanted to run a TQ you'd need to find a superquad, electric choke conversion parts if those exist, or rig up a manual choke.

aftermarket dual plane spread bore options are: performer, weiand 8007, or offy 5685.


if you like tuning carbs, TQ's are great. if you want to put something on and not have to fuss with it there's better options. options that involve not hunting down parts and paying thru the nose for them.
 
When you hit the reply or quote button, type outside the quote tags. They will have a bracket “[ ]”

I have run the LD modified as per the book and have done so without issues on a low compression 318, mild Hyd. cam,, 4spd manual & 4.10’s.

The carb was the 440 TQ. It has the same size primaries as the Holley 750.

Run it, have no worries or fears.
 
junkyardhero said:
performer rpm is a square bore, which means you'd have to run a spacer/adapter. also no choke well. so if you wanted to run a TQ you'd need to find a superquad, electric choke conversion parts if those exist, or rig up a manual choke.
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No conversion parts available.
Be crafty…..
junkyardhero said:
aftermarket dual plane spread bore options are: performer, weiand 8007, or offy 5685.
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(For the OP just incase…)
The Offy is over a $600 intake.
The Weiand's have no choke well.
(Or coil mount bosses)
The Performer is a light weight stock replacement intake that has the choke well.

junkyardhero said:
if you like tuning carbs, TQ's are great. if you want to put something on and not have to fuss with it there's better options. options that involve not hunting down parts and paying thru the nose for them.
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Better options! I agree.
TQ parts are available at (IIRC) The Carb Shop.

Everything is pricey no matter how you slice it. Check rod or jet pair prices for Edelbrock carbs vs The Crab Shops TQ rods and jets. They also have rebuild kits.
 
junkyardhero said:
oh wow, that's neat!

i figured something like that existed, or you could cobble something together that was workable.

however, this new information does not color my thoughts on the TQ
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I did see that TQ's can be found and they start around $450 to as much as $2100.
 
The car hobby is expensive but what hobby worth doing isn't. Besides they are fun and you get to meet different people.
 
Dan the man said:
I did see that TQ's can be found and they start around $450 to as much as $2100.
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are you for real?

there's several on the classifieds right now that are sub $200, they're all over ebay and offer up and CL, you can get them at swap meets all day. **** man, i have TWO sitting right here: a superquad with electric choke and a 440 HP2 unit that i'd take peanuts for.

numbers matching, rare TQ's sure, they command big money. but a bread and butter one that'll work for just any old small block? you can get those all day, every day and twice on sunday for the cost of a nice dinner out.
 
junkyardhero said:
thanks for the addition, it's been awhile since i've held one so i'd forgotten about the lack of those
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Ahhhh, ain’t no thing. I figured it would be good info who ever stumbles on in. You never know who is reading. I figured a new guy to the car hobby and MoPars might like to know this stuff.
May even help somebody from getting really pissed off?
lol!
 
rumblefish360 said:
A big huge thank you!
I love being proven wrong with the added bonus of possibly getting one.

THANK YOU!!!!!


$450? Pro rebuilt, awesome looking.

$2100 = Crack head pricing.
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At $450, going by the photos they looked great. $2100, like you said
 
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