1971 340 Cuda surges while driving steady. I think I can adjust the Rods with the center screw to help with the surge. Which way to turn the screw, cw or ccw to raise the rods out of the jets.
Thanks Bob

have you looked for other things like vacuum leaks, too much timing etc ?

The car runs very good and does not ping. I will check the total timing and vacuum again. Don't think it's that but I could be wrong.
Bob

Some motors will surge with too much total timing. Throw a light on it, find out what the initial is, the mechanical and the vacuum if your running it. If you are running the vacuum, try disconnecting it and see if the surging goes away

It could be lean surging; turning the metering rod tree clockwise will raise the rods out of the primary jets and richen the cruise mixture.

Try creeping up on the rod tree gradually and drive at cruise to see if it helps with the surging.

If it has a 71 TQuad on it metering rods do not adjust that is a 72 and later.

This^^^^

Back after the long winter and just looked at my carb. TQ K0 4973S Oct 1970 340 auto and it has a adjusting screw on the metering rod bridge. Whats with that?
Any info
Bob

A pic may help

Yes. Depress the metering rod primary piston until it lightly bottoms in the bore. Hold it there. With a small screwdriver, turn the screw counter clockwise until the primary piston stops going down. Then, slowly turn the screw clockwise taking note where the primary piston starts to move up. From the point it begins to move up, turn the screw 1 1/2 turns clockwise. This is a starting point. From there you can fine tune it by turning the screw clockwise to richen the mixture and counter clockwise to lean it.

https://www.youtube.com/watch?v=Dwh6SQ7kV6E

yes, that is how that screw is used for adjustment.
it rides on a cam that is in the base plate.
lots of adjustments on a T-Quad.
at one time, carter had a great book on choosing, adjusting, and tuning the T-Quad. this book also listed all the base plate numbers and what those numbers were installed on.
jets, metering rods, and other parts were also listed.
as that book has been out of print for a while, i don't know where you would get a copy.
chrysler also published a book under the master technicians service conference series.
it was titled "The '72 Thermoquad Carburetor", reference book 72-1.
that has some good info in it as well, but again, i don't know where you would get a copy.
i would offer to put these books into a PDF file and send them out to those interested, but it would be a while, as i'm having hip surgery tomorrow.
maybe if anyone is interested, i can do this in a few weeks. PM me then to see if i am able to get around good enough to do this.

Well after taking the picture, I can now see it is not a screw slot on bridge but the way it's made.

Great advice moparx!

I've got a pile of the Carter TQ literature here, some of it scanned already.

A few of these are up on my web server, you can get them here:

1) TQ Service Manual

2) 1982 TQ Tech Guide

3) 1972 TQ Reference Book

NOTE: if you try the above links and you get nowhere, try again a bit later, I may have the web server down for some maintenance of changes.

Thanks for all the great info
Bob