automatic and Manual thermoquad difference.

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ajarofclay

ajarofclay

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Hey all, I'm doing my best to get my car back to as close to stock as I can. I picked up an original thermoquad for it but it's a 6138 (4spd carb) and my car is an automatic so it should be a 6139. I currently have a pretty big stall in it but also have an original convertor I am putting back in. All the browsing I've done doesn't really show any differences. Does anybody Know the differences?? I've got a strip kit if it's needles, seats, rods, etc. Also, does anyone have a carb rebuilder they're a fan of. I was doing it myself and have everything all cleaned up and realized that it needs to be bushed. Thanks in advance for any input, fellas. And possibly Ladies. :)
 
There may be air bleed differences, not sure. Why not try Woodruff, the sponsor on this website.
 
Bewy said:
There may be air bleed differences, not sure. Why not try Woodruff, the sponsor on this website.
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Dang, that never crossed my mind. For the most part, I'm oblivious to advertising. I actually came upon a place online not to far from me and requested a quote but I'm open to explore more options so I'll check them out. Cheers, Mate.:thumbsup:
 
An older member a while back (Demonsizzler) had said something about the manual trans carbs being a slight richer and/or a bit heavier on the pump shot.
 
this might help

Image (2).jpg
 
part number group 48 pump jet different, group 53A pump lever different, group 75 metering rod same . Group 115 throttle connector rod different between s and sa carbs
 
That graft is just adjustments, you need one that shows rods-main jets and idle air bleeds. But I doubt there was a difference in them.
 
Here are the numbers I have listed per Gary Lewallen.

Model| Application...................| Pri....| Sec...| Rod...| Bore...| Kit
6138 | 72 340 MT F (3614122) | 4095 | 5137 | 1940 | 1-3/8 |1
6139 | 72 340 AT F (3614123) | 4095 | 5137 | 1940 | 1-3/8 |1

Based on that, looks like it is either the bleeds or adjustments that make the differences.
 
A few years back I bought a hard to find AVS 4933S for my 70 340 4 speed Duster with CA Emissions at Carlisle and dropped it off at a place called Dated Components (Hamburg, PA) who had a spot in the swap meet. It was not cheap but they made it look like it was brand new. Re-plated everything and I got it back roughly 6 weeks later. Kind of a waste for my car. I was thinking about selling it to someone looking for a factory correct carb for a concourse restoration.
 
Parts list 75-1940 metering rod .072 x .060 x .045 both carbs 120-4095 primary metering jet both 120-5137s secondary metering jet assembly both carbs
 
Ceedawg said:
That graft is just adjustments, you need one that shows rods-main jets and idle air bleeds. But I doubt there was a difference in them.
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Yeah, that's the same details that I came across. My car actually has higher compression and bigger valves than the downgrades that happened in '72 so I think it'll be alright.
 
Do you have the s carb or the-sa carb? the s only is orginal sa is later engineering change. 48-365 pump jet and housing assy carb 6139 48-370 pump jet and housing assy carb 6138 48-369 pump jet ,housing assy for export carb. 3 different parts might make a difference. 53A-518 pump operating lever assy carb 6139 53A-544 pump operating leverassy carb 6138 . two different parts. In adjustment data pump stroke is 9/16 for carb 6138 and 1/2 for carb 6139, two different settings
 
Bugman said:
Do you have the s carb or the-sa carb? the s only is orginal sa is later engineering change. 48-365 pump jet and housing assy carb 6139 48-370 pump jet and housing assy carb 6138 48-369 pump jet ,housing assy for export carb. 3 different parts might make a difference. 53A-518 pump operating lever assy carb 6139 53A-544 pump operating leverassy carb 6138 . two different parts. In adjustment data pump stroke is 9/16 for carb 6138 and 1/2 for carb 6139, two different settings
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pump stroke and lever assembly might be a little tricky. I've got a strip kit if I need to play with it. I appreciate all the input though. Thanks so much.
 
Idle air bleed size, main system air, idle jet size,etc last year for that info from carter 1969. Wild guess 1972 was not air bleed carb,first year for solid fuel.
 
Bugman,
Thanks for posting that info. The Carter document in post #10 is the first time I have seen Carter reference the cfm [ 800 ] outside of their aftermarket catalogs.
 
ajarofclay said:
Thanks to all. Great information. Robert, I have subscribed to your Youtube channel.
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Me? If so, THANKS! I have to learn more about and on the YouTube platform. I’d like to do more but also want to focus on my personal junk and not the wife’s or sons. Which I’m stuck in a mire on.
Wish me luck! LMAO!
 
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