Demonizer71
Well-Known Member
Can you run a Manual spec Thermoquad on an automatic car? All t-quads look very similar. Whats the difference and would it be ok to do this swap?
6138 vs 6139 thermoquad
- Thread starter Demonizer71
- Start date
-
AdamR
Big Member
Im not sure what the difference is but I would like to know as well.
demon sizzler
Well-Known Member
- Joined
- May 26, 2004
- Messages
- 182
- Reaction score
- 6
You can use either one in place of the other; the 4 spd carb has leaner circuitry to allow the engine to idle down more slowly. This is accomplished by a different dia metering rod with larger steps which leans the circuitry. Also, note that a 4sp carb has an extra lever for the accelerator pump linkage on the throttle shaft for an extra pump shot. See pics:
1st pic is a 6138,
2nd pic is a 6139.
1st pic is a 6138,
2nd pic is a 6139.
Demonizer71
Well-Known Member
Ahh Sizzler I was hoping you'd answer this thread! I have the car running now but it is stumblin bad between primaries and secondary transition. It had a 9058 440 thermoquad on it. I could not get the secondaries to open fully with that carb and the 6138s I have is literally brand new. The motor has a "purple"cam shaft (280 duration 60 overlap,474 lift 110 centerline) has been blueprinted balanced and has an "m1" single plane intake & headers. So I have no clue how to setup my jets or timing etc. I just put vacuum gauge on it and advanced the timing but it isn't happy at all now. pinging and rough. I'll back off the timing but I'm not well versed in hot rodded mopar tuning!
Demonizer71
Well-Known Member
the 440 carb jets were each a good 4 turns out from bottom, car ran well but again could not get secondaries to open past half way to full open. I have the 6138 on it now, sounds like it want lots of fuel I guess.
demon sizzler
Well-Known Member
- Joined
- May 26, 2004
- Messages
- 182
- Reaction score
- 6
The cause depends on what rpm or mph that the stumble is occurring. Also if the pull-off is weak or bad, it can cause the stumble. And since it is a '72 340 carb, the cause is easier to track down. What I would suggest from a mechanical standpoint would be:
fire off the engine, remove the air cleaner(keeping appendages out of the fan!)and push down on one of the air door dimples,
the air door should drop down .150"-.250" below the rear air door stop. If the air door has none of this slack and is tight against the air door stop, remove the pull-off linkage at the pull-off and bend the rear crook of the linkage a little bit rearward and re-install the linkage. This will give you a bit of needed slack in the air door.
Also the top of the carb should be casting #6-2007 or 6-2080. Tops do get replaced improperly over the years and can affect performance, David.
fire off the engine, remove the air cleaner(keeping appendages out of the fan!)and push down on one of the air door dimples,
the air door should drop down .150"-.250" below the rear air door stop. If the air door has none of this slack and is tight against the air door stop, remove the pull-off linkage at the pull-off and bend the rear crook of the linkage a little bit rearward and re-install the linkage. This will give you a bit of needed slack in the air door.
Also the top of the carb should be casting #6-2007 or 6-2080. Tops do get replaced improperly over the years and can affect performance, David.
-
