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Hey Howard and Jerome,

Can't thank you both enough for the insights on all this. Couple things I can answer about my transmission, and things I'm going to keep working through. I had some time tonight to take the care out for a longer drive to get a sense of some of these things. I recently put a new gas tank in it, and this was it's first time going to a gas station in who knows how many years. Never thought I'd enjoy going to a gas station so much as I did today! But anyways...

Howard - can confirm the Direct Drive is working. I followed the procedure outlined in the service manual as best I could (without the special tools described) for adjusting the linkages to ensure nothing was dragging. Neither heard nor felt anything (other than how horrible by tires are), but the RPM definitely drops and the engine goes silent when cruising. It'd kick back up (or "kick down" as they describe) with more throttle. 0-65 felt really pretty normal. And no worries with the Low to High shift. My Low gear just puts the car in neutral - going to try adjusting the Low band screws. By the end of the night, I had the Park idle at 510 or so, and the High idle at about 310. Bringing it to 375 in high was bizarre, though. I would turn the idle screw and nothing would change (or it would be minimal). I basically had to double the distance the screw was pulled out to achieve the 375, but then of course putting it park brought the Park idle to like, 750. That screw has an immediate effect when the car is in Park

The car does still idle well at 310, and I don't get a sense of hesitation on acceleration, or concern it'll stall. So I'm not sure if this is really a problem at all, other than it's just not "right."

Jerome - super, super helpful. When I had the linkages apart, I made sure it went back together with the lever very nearly seated. The transmission fluid situation is... not great. I do know it's Type F, because I've emptied it twice in changing the pan gasket (thinking I screwed up the first gasket, only to find out/realize that the source of my leaks are all of the seals). I do check the fluid often and always refill it following the procedure outlined in the manual. I will say, shifting from park to high is smooth - a gentle bump if you will. Low isn't functional. Reverse is often a hell of a jolt, though I'll occasionally get some smoother shifts here, too. The transmission is definitely due for a proper/complete overhaul, just not in the budget at the moment.

I do have a couple things left to do with the carb, and I'm not sure this idle issue doesn't come back to that. The engine is FINALLY no longer running rich, but I have the thermostatic choke capped because the line rotted away at the exhaust manifold. I just have the choke wide open all the time - not sure how (if) this would effect the fast idle, but getting the choke to function correctly is on my to-do list as well.

Please let me know if you have any other suggestions on this. I appreciate this all very much.

If it idles well at 310, I'd say leave well enough alone, but I might also ask how you bare measuring RPM, because 310 is quite slow and I would think down at that speed the idle would be lumpy at best.

I find to shift into reverse I want to make sure the engine speed has dropped down before I make the shift - don't be in a hurry.

Sounds like you have changed the fluid a few times, that's great. The torque converter has drain plugs, part of the procedure to drain the oil requires draining the converter via those plugs, so hopefully you did that too, if not, next time.

Setting the idle speed is a two part process. There is the idle speed adjustment and the idle mixture adjustments.

I set the idle with the engine in neutral and fully warmed up with the choke in full open position.

First, I set the idle speed to the desired rpm with the adjustment screw.

Then I adjust the idle mixture with the two jet screws at the base of the carburetor. Usually start out with the mixture jets screwed out one and one-half turns. Then screw one of them in until the engine starts to slow down and screw it out about one-half turn. Repeat for the other idle jet.

You may need to adjust the speed adjustment again.

Repeat procedure until you achieve the desired rpm.

I have the air cleaner installed when doing this.

It is also a good idea to disconnect the distributor vacuum chamber tube from the distributor and plug it. This usually not necessary, but insures the vacuum chamber is not being activated. More of a belt and suspenders thing.

Some use a vacuum gauge to optimize the idle mixture adjustments. This is a good idea.

Hope this helps.

Hey guys - checking on all this. In the meantime, I'm an idiot and missed that there's a hole near the very bottom of the carburetor that's wide open, right behind the throttle assembly. Gas comes out of it when moving the throttle, would imagine this adds a vacuum issue as well. I can't imagine this is supposed to be there (wide open that is). Is there a plug or some missing component that needs to find its way back on? Thanks very much...

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In my car, which granted is a 1953 327 with a 4 barrel, coming right near there is the hard vacuum line that goes to the vacuum advance on the distributor. The line runs over the top of the engine. Maybe that? The other would be a vacuum line to the windshield washers, typically involving a line also to the vacuum side of a dual action fuel pump as sn assist. Also a possibility.

I THINK it's for the starter switch. I think that's the little dark hole in the diagram. I don't see anything about in the literature dealing with the starter switch, but that seems to make some sense. I put my finger over it while the engine was running - doesn't seem to draw any vacuum, and my guess is that the check ball for the starter switch blocks the port when vacuum is present.

I wonder if I need to make an adjustment to the tongue of the anti-perc arm. I don't think the metering rods are fully seating at idle, and the pin on the vacuum piston stops on the tongue. So my current theory is that when it's in the park (and vacuum is highest), I'm getting an artificially high idle because some fuel is still making its way through the main jets. Does this seem plausible?

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Believe the little hole is the air intake for the starter switch. When the engine is stopped a ball inside a passage falls down to complete a mechanical connection between the throttle shaft and starter switch. When engine starts the ball is supposed to be sucked up by vacuum onto a seat where it can block the port so no more air can enter. The fact you have gas coming out the port makes me wonder how worn the throttle shaft or the shaft bore in the casting might be. On some carbs that wear can be an issue and a huge source of vacuum leaks that could cause a fast idle. Fix depends on the cause -- either a new shaft or a bushing in the bore or maybe both.

Here is a photo of my WDO (different number) with the same port on the side and a generic drawing and description of operation for the starter switch. The layout illustration shows a typical construction and in particular the ball that is supposed to seal any air leak.

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An air inlet wouldn't make sense for the starter switch as it's air comes from the intake manifold so I suspect the hole should have a press-in plug. My 1951 has a nearly identical carburetor but unfortunately it is some distance away so I can't run out to check.

Disagree Don. The passage the ball works in is connected at the top to vacuum via passages inside the carb so the bottom needs another opening so the vacuum could have something to pull. If both ends were connected to the manifold both would have vacuum and nothing would happen. In this case the bottom end is left open to air and there is a screen inside to keep any debris from being sucked into the components.

As soon as the engine starts vacuum is present at the top of the passage and when the accelerator is released by the driver the ball is sucked up away from the throttle shaft breaking the mechanical connection so the accelerator can no longer activate the switch. Ball is pulled tight against a machined seat in the passage and is held there to seal off any farther air flow until the engine stops and ball loses the ability to stay up. It then drops down and everything is set up to be ready for the next start.

Thanks, guys! Super helpful. I ended up making several adjustments to the anti-percolator, both bending the arms down so they interact with the studs, and lowering the tongue so it no longer interferes with the vacuum piston and the metering rods fully seat in the jet when under vacuum. At the very least, the anti-perc seem to elimate the brief "gurgle" I'd get after revving in park. The engine speeds did get closer, too - 330 in high to about 520 in park. A lot better than it gunning up to 700.

Howard - looking at your picture, the big difference I see is your fast idle screw. I've found on mine that when I try to adjust this, the choke plate just gets stuck and can no longer fully open. Not sure what time doing wrong with that, but I just have the screw backed out so it doesn't interfere with the operation of the choke.

Jerome asked how I'm measuring engine speed. I'm using a digital photo sensor, with the reflective tape on the belt. A better place/tool for this operation?