Thermoquad identification help!

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73drtsport

73drtsport

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Hi there, I recently picked up a TQ and id love to rebuild/get it rebuilt professionally. I've been searching threads, forums, and elsewhere on the web trying to figure out what year it is and basically the basics of it. It's got 1.5 inch primaries so pretty sure it's an 850 but I'm new to these beautiful creations! I'll post some pics I know there's some gurus here that will know more than I! The two numbers stamped on the back driver corner are 9117s and 22977. I'm really just curious if it's a good one worth rebuilding? Id like to put it on my 360 paired with an rpm air gap. Running a Hughes cam .540 lift and comp roller rockers/push rods. Thanks!

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73drtsport said:
Hi there, I recently picked up a TQ and id love to rebuild/get it rebuilt professionally. I've been searching threads, forums, and elsewhere on the web trying to figure out what year it is and basically the basics of it. It's got 1.5 inch primaries so pretty sure it's an 850 but I'm new to these beautiful creations! I'll post some pics I know there's some gurus here that will know more than I! The two numbers stamped on the back driver corner are 9117s and 22977. I'm really just curious if it's a good one worth rebuilding? Id like to put it on my 360 paired with an rpm air gap. Running a Hughes cam .540 lift and comp roller rockers/push rods. Thanks!

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78 Smog 440 carb. I have a 74 360 thermoquad available if you’re interested.

Jake
 
xLURKxDOGx said:
78 Smog 440 carb. I have a 74 360 thermoquad available if you’re interested.

Oh copy, from what I've read the smog ones aren't quite as desirable. I picked it up for $75 bucks so I figured it was a pretty good deal. Is your 74 an 850cfm?
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As you can see im really new to posting on this forum even though I've been a member for a few years. Ha I put my reply in your quote
 
That's a mighty big cam for a thermoquad. Generally, they do not like a lot of duration because of the low vacuum signal at idle. It causes the metering rods to bounce up and down causing a constant rich lean condition and erratic idle. There's not a ton you can do about it. They will run like gangbusters with a big cam, just not idle too well.
 
That carb is fine. With a big cam a Carter needs a lighter metering rod spring, like a holley needs a lower power valve
 
Marcohotrod said:
That carb is fine. With a big cam a Carter needs a lighter metering rod spring, like a holley needs a lower power valve
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So enlighten us big guy. Who makes custom Thermoquad metering tower springs? I've heard of removing them altogether, and tried it but it's not effective.
 
Marcohotrod said:
That carb is fine. With a big cam a Carter needs a lighter metering rod spring, like a holley needs a lower power valve
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The power valve on a Holley is NOT affected by idle vacuum, idle speed or idle roughness. Lowering the power valve opening timing is a criminal tuning mistake.
 
RustyRatRod said:
That's a mighty big cam for a thermoquad. Generally, they do not like a lot of duration because of the low vacuum signal at idle. It causes the metering rods to bounce up and down causing a constant rich lean condition and erratic idle. There's not a ton you can do about it. They will run like gangbusters with a big cam, just not idle too well.
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10-4, I did read on another post somewhere they were hard to dial in at idle with a big cam. Im gonna rebuild it and see how she runs I want to hear those secondaries in real life! Thanks for the input fellas this forum is awesome!
 
The 9117S Thermoquad fit 78-79 Dodge truck with a 440 & it's probably a low performance smog carburetor. They can be built for your small block, but parts are getting scarce.
 
Carter made different metering rod springs . Edelbrock has them for AFBs I would find / make something to work. and for starters clean it and try as is. and a 1978 Thermoquad is similar to earlier units - it is not a vastly different low perf. smog unit!
 
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Marcohotrod said:
Carter made different metering rod springs . Edelbrock has them for AFBs I would find / make something to work. and for starters clean it and try as is
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Yeah my brother has a 440 in his 73 charger and he's got the tq/Carter adapter plate we're gonna clean it up and see if it will work before I do a complete rebuild.
 
Come to find out my brother has the thermoquads a couple 6000 series! Might end up getting rid of the smogger we'll see
 
Post the numbers & someone can tell you which one would be best for your application. It's be 10-15 years since I rebuilt any Thermoquads & I've forgotten all of the little tricks to make them perform well.
 
if your wide open for more than 6 or 7 seconds the stock street thermoquad small .09? seat has trouble flowing enough. Carter had .120" or so needle and seat in the strip kit-I know they are hard to find-but all I could get for 1 was $120 in 2013. anyone drill seats larger?

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Demonracer said:
Post the numbers & someone can tell you which one would be best for your application. It's be 10-15 years since I rebuilt any Thermoquads & I've forgotten all of the little tricks to make them perform well.
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I'll get some pics of em
 
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