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1977 Dodge 440 carb help

7K views 16 replies 9 participants last post by  chriswelds 
#1 ·
I have motorhome with a 1977  dodge 440 and when I got it the carb was a Edelbrock. I have had nothing but trouble with it being stranded twice and once after getting it rebuilt. Flooding is the problem and everything inside the carb has been checked twice. I would like to go back to the stock carb which I think is the Carter Thermo-Quad TQ 6545S. I have several questions.

1. Am i crazy to switch out the Edelbrock as everyone says its a good carb? (apparently not for me)
2. Where do I get a Thermo-Quad?
3. Is the stock 1977 the best one or do I  have some other choices?

Thanks for any advice and help.

Ray
 
#2 ·
Earlier Thermoquads are better if you don't need a "smogged up" TQ that had all sorts of emissions crap added to it.

850cfm version to feed the 440
 
#3 ·
ChrisKD said:
Earlier Thermoquads are better if you don't need a "smogged up" TQ that had all sorts of emissions crap added to it.

850cfm version to feed the 440
Yeah then you can send me the junk Eddy. ;)
 
#4 ·
2. Where do I get a Thermo-Quad?




You can still find the T/Q at some salvage yards but will most likely will need built. heck i'm sure if you look around on this site (classifieds) you could find one>
 
#5 ·
I have one off an 88 but that won't help you much and YES it needs rebuilt.
 
#6 ·
jha79 said:
2. Where do I get a Thermo-Quad?

You can still find the T/Q at some salvage yards but will most likely will need built. heck i'm sure if you look around on this site (classifieds) you could find one>
There's also a website that sells em, can't remember the name of the place though. And they'll even customize it too if you want.
 
#8 ·
#9 ·
IMHO a well tuned TQ cannot be beat - and you can do about anything on them without removal.  They do have couple of O-rings in them that will start leaking and need replacing about every 10 years, a sure sign you waited to long to re-build/clean.
 
#11 ·
mopar65pa said:
Man what was I thinking. :-[ I have 3 of those that need rebuilt, I was thinking quadrabog....... ::) {hammer}
The Thermoquad is very easy to rebuild Tony, i'd rebuild a TQ over any other carb any day of the week, especially a quadrajunk.

And i know someone is gonna mention it, the infamous Bog between the Primaries and Secondaries, it can be tuned out and the transition from Primaries to Secondaries is smooth.

The TQ also offers great gas mileage, provided that you can keep the throttle off the floor :p

I'm running an 850 TQ on the 340 in my Duster, my dad and i rebuilt it and tuned it. It's the best the 340 has ever run. I ran an AVS on it, several Quadrajunks, a Hoggie (holley), ect. The AVS was pretty good but the Body was cracked and it slowly seeped fuel out, The Quadrajunks constantly vapor locked (i smashed em with a BFH to vent my rage) and the Hoggie {puke} had problems from day 1 (new).. Left Bank ran super rich, Right Bank ran super lean, and no matter how hard my dad and i tried we couldnt fix that issue.

I unbolted it and ran over that damn carb with the Bulldozer ;D Bought a Thermoquad and never looked back
 
#12 ·
I have a '72 thermobog manual on digits. I mean pdf.

I have tons of info for the qjet.

Mike does bring up a good point. Fuel pressure, AND NOT TOO MUCH. Often times between 5-7 psi, some will tolerate a little more, others a little less. Modern trend is even bringing down psi to around 4, and rejetting as required. They say delivery is more stable this way.

Chris, there are numerous reasons/cures for vapor lock. Of course, a shield/carb spacer will almost always do the trick unless you have a pinched line/pin hole/faulty pump.

What's the matter? I thought people liked to "feel the secondaries come in"  ???  ;D I guess the feel of bogging is not good?

As you have found, ideally you will tune it out, so transition is TRANSPARENT. If it bogs, it's coming in too soon. If it kicks, it's coming in late. If you hear/feel nothing, it's spot on.
 
#13 ·
joe s said:
Chris, there are numerous reasons/cures for vapor lock. Of course, a shield/carb spacer will almost always do the trick unless you have a pinched line/pin hole/faulty pump.

What's the matter? I thought people liked to "feel the secondaries come in" ??? ;D I guess the feel of bogging is not good?

As you have found, ideally you will tune it out, so transition is TRANSPARENT. If it bogs, it's coming in too soon. If it kicks, it's coming in late. If you hear/feel nothing, it's spot on.
I did try a Spacer, tried routing the line away from any heat source (ie exhaust, alternator, ect) somebody once told me wrap/shield the lines, tried that too. (All new lines and hoses on the duster at the time)

I can't speak for others, but i like my carb tuned so it doesnt kick or bog when the secondaries open.
 
#14 ·
ChrisKD said:
I can't speak for others, but i like my carb tuned so it doesnt kick or bog when the secondaries open.
Ever hear someone talkin about "I love when the secondaries kick in"? Just about as stupid as the ricers saying "I love when the vtec pops" the modern day equivalent of a secondary. We would spend a lot of time on a chassis dyno trying to eliminate the bog or sudden thrust, either of which is slowing you down.
 
#15 ·
MT_84Ram said:
IMHO a well tuned TQ cannot be beat - and you can do about anything on them without removal. They do have couple of O-rings in them that will start leaking and need replacing about every 10 years, a sure sign you waited to long to re-build/clean.
I agree.. a well tuned TQ is the best street carburetor you can get IMO. Pretty d@mn good race carburetor, too :)
 
#16 ·
joe s said:
Ever hear someone talkin about "I love when the secondaries kick in"? Just about as stupid as the ricers saying "I love when the vtec pops" the modern day equivalent of a secondary. We would spend a lot of time on a chassis dyno trying to eliminate the bog or sudden thrust, either of which is slowing you down.
The only good Sudden Thrust is that one when you go WOT from a dead stop :p, But that's a different thrust than the secondaries kicking in ;D

Although i do recall saying "I love when the secondaries kick in" Cause i was talking about my '84 W50.. For a loong time the secondary (lmao..secondary) would stick shut and i was lucky if would open for a change, so i'd say "boy i love it when that secondary actually opens" :p
 
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