..........I am getting my Plymouth closer everyday that I play with it, I have a question on the metering tree height. I had the tree at 1 turn, and it was lean off idle, (not smooth) I raised the tree and it is much smoother, but still slightly surges at off idle speeds. I can see the tree going up and down, like it is searching for the right spot. It is now at 1 1/2 turns, I have tried the timing in different spots, and it doesn't seem to change. How far out can I raise the tree? It is a '73 340 with a .48 purple cam, 2.02 intake valves, 10 to 1 pistons, stock electronic distributor, with the advance plugged. It doesn't run well un-plugged (before you ask.) The spark plugs look great. The carb is a '72 auto trans version. Idles good, is responsive........when you put it in gear, it doesn't stall.........the rpm's just seem to wander slightly at speed. Maybe it needs a load (as in driving) on it? I haven't been able to try that yet, the roads are still too crappy here. Please advise, give me more things to tinker with. I will get it, I am close. Thanks.

OK! Sounds like you are close. You have almost the identical setup we had except it was a 6bbl.
Take out the spring that returns the tree and let the tree rest down. With a cam, the low vacuum will cause it to be erratic. It should move with the throttle unless there is no lever inside. Without opening up the carb, look around for metering rods #'s 1996 or 1997. They are not stock, they are from the '80's tunning kit that Direct Connection sold. Most TQ's have .095 primary jets and if you use a nice tiny rod they
should do alright. Take out the rods and notice the profile, if it has two definate steps down to fairly small, keep them. Late smoggers have almost no taper down, they are lean and the suck unless you jet up a couple sizes. I kept a log of all my builds from 1982 until now, so if you have a spare carb to work up, leave yours running for now. Glad to help with TQ's as you either love'em or you don't. Oh yea, 1-1/2 turns from all the way down is where to start, no lower or they will
just sit there until about 1/3 throttle.

Ok, thanks, I will check mine. I tried to find my spares, I thought I had 2 spare sets. I can only find the smogger ones, #2014 I think they said. (Jesus, that writing is small!) I will look again tomorrow, I thought I had another pair somewhere. If I end up needing them, who sells the correct size?

Too much cam for the stock metering rod piston spring. You will need a much lighter spring(tension)for the carb. Less vacuum=less spring tension. If you have a simple ball point pen with spring loaded action, get the spring and 'stretch' it in the middle a bit and install it. This should stop the metering rod tree from bouncing, David.

Sorry about where to find...The old D.C. race bible has specs for stock-eliminator race use,
won't work for normal app's. I will dig out my stuff and send you some diameters this afternoon,
then you can look and compare. Have a micrometer, small drill gauge or dial caliper to measure?

Thank you David, I will try that next. I found a Government pen, that should do it for the spring! I can't steal them from work anymore, they stopped making them!

Well now we BOTH know where to get our parts! The end step is .035" on 1994/5/6/7 rods. Look for that as it is the power step before the 4bbl. The #1996 is .069 to .048 to .035 and the #1997 is .067 to .045 to .035. There are a few cometition-series with no mid-step, #16-634 is .062 to .030 and #16-633 is .055 to .040 which
would give you more off idle fuel, may or may not need that. My next project is installing my M1 intake with a prototype dominator-to-TQ adapter!
Good luck...another Dave.

Ok, here is where I am at today. The spring from a pen stopped the surging, it will hold at speed now. But it still isn't as smooth as I would expect at speed. Did I bend the spring too much? I tried to match the length of the original.........I made it about an inch and a half long. And I had to put a small washer in the hole to keep the spring from going down too far. Or should I try a different set of metering rods next? Thanks, you have helped a lot, every day is a little better.

Hook up a vacuum gauge (sears has them) and measure the manifold vacuum at idle. The TQ will need about 10 inches of Hg at a hot idle in gear to keep the metering rods seated.

Did you try advancing the initial timing to 14 to 16 degrees?

If you are running a single plane intk, then maybe shoot for 16 to 18 degrees initial.

I fought with the metering rod tree spring trying different spring tensions all last summer. I finally took mine out entirely, with the big flat tappet cam, tunnelram and 2 thermoquads it worked much better without the spring. The cam is 272/274@.050, the thermoquads work perfectly now. good fuel economy, explosive acceleration. Dave

since i'm fiddling around with my TQ with the sames symptoms, too, this thread is very intersting!

what i would like to know is: what exactly does the spring do? and why does a lighter spring help stabilizing the tree? from my understanding it should be the other way round ... can someone explain this to me?

Well, from what I am learning, with a high lift cam (low vacuum) like mine, the tree acts differently. You could see my tree going up and down as it was surging, it was fighting the spring tension. Demonsizzler recommended a lighter spring, and it is steady now. Lower vacuum needs a lighter spring. I am going to put my vacuum gauge on it next, I finally found it. It was in one of my many parts boxes still full from moving! I am going to re-jet it next, it is still lean. My plugs still look great, a slight brownish color, the idle is as smooth as one would expect with this cam, (It sounds nasty) and there is no off idle bog when you punch it. It is right there. Getting the choke adjustement right was the worst part of this so far, and that seems fine. God, it ran like s__t when I first started it! Got it good enough to hold it at 2500 rpms to run the cam in, but it wasn't happy. Everything I do makes it a little better, in steps, thanks to this site, and helpful people like the folks above!

If anyone has access to a TQ strip-kit .. there should be a selection of springs(I believe color-coded) in there. Someone else was supposed to put together a metering-rod-tree spring-package but it appears now they never did.

Maybe I should. I came out with a new and improved Air Valve Tool ...so a simple package like this should not be a problem.

R T ....I have a couple of regular Strip-Kits also and it did not have a spring in it either. But there was some sort of "package" that Chrysler offered that DID have those springs in it.

This topic has me thinking about this ... I think that those kits with the springs were offered in the Hustle Stuff or the very early Direct Connection catalog.