Terry, does your car still have the flapper valve in the exhaust manifold hooked up? If so is it free?

It's still there, it's loose but the spring is broke. I have it wired open...the counter weight is towards the block. When this happens, the idle isn't horrible, the car doesn't die, but it is noticeable. I hope the flapper valve is wired up in the right position.

Yes, toward the block is in the wide open position.

Terry, there are so many things that can cause the concern you described. Do a quick check on the vacuum advance and the dist.timing. Make sure the points are set correctly, if so equipped. The counterweights inside the base of the dist. can be sticking, and when it is at low RPM or shut off, they return to there base. Also, have you checked and verified that both carb's return completely to their respective base idle stops?. When you adjusted the carbs, did you remove one of the linkages to one of the carbs?. That is required to get a proper setting. Adjust the one linkage to match the other after that procedure. A quick and easy way to see if the throttle plate is sticking in either carb., while it is running, and running poorly at idle as you describe, see if you can apply slight pressure making the throttle plate close better. Do this on each carb individually, see if that makes a difference. It sounds like the carbs are not synchronized properly, and/or the valves could need adjusted. When was the last time the spark plugs were changed?. Modern spark plugs don't clean themselves very good, and any type of stale fuel, over saturated fuel with additives, and/or poor secondary ignition can cause the same effects

I'll try closing the throttle plates by hand next time I have the car running. I've set the carbs according to the manual and it has been good for over two years. I've put in new points, plugs,cap ,rotor, condenser and have excellent steady vacuum. One set of points I couldn't get open to .020 so I bought another set and the new set worked. I do have one plug wire that has more resistance than the others ...according to their length....about a third more, so I'll put new wires on. I'll pull the dizzy and check it out this next week...I always remove it when setting points....my dwell was not perfect, 37, but with the old needle movement meter I have the difference could be in the margin of error. I haven't heard much about the throttle shaft needing to be rebushed on these carbs like the Q-Jets are famous for but I think that might also be a possibility. I did lightly spray with brake cleaner the base of both carbs while idling, but nothing changed. Terry

I had the same symptom problem with my 52 Hornet Terry. The problem was the valve adjustment according to the recommended setting was too tight. When the engine got warmed up, especially on highway driving, the valve clearance got tighter from valves lengthening. When stopped for a few minutes it would start right up and run fine until the valves heated up again. Per Walt's recommendation adjust vales int. .014 and ex. .017. engine cold. . I have not had this problem since. Apparently todays gas causes the valves to run hotter reducing valve clearance. which may cause some valves to not seat. Good luck.

I remember setting the valves to .012 and .014 respectively. I set them after a 90 mile highway drive and letting the car sit for about an hour. I was removing the single two barrel carb and intake for the dual set up. With the intake/exhaust off, it was easier to get at the valve side covers. I had read what Walt recommends and at some point had intended to open them up to that spec but have not done so. I intend to remove the heat riser valve after the driving season and at that time I'll adjust the valves to those specs. It's been raining and even snowing a little here so I'm at the mercy of the weather, as usual! Terry

You are welcome. You will be a very happy cruiser after you do. Don't forget to recheck carb, balance and adjustments after valve adjustments. Just checked your weather, 44 degrees (burrrr) and rainy. 77 degrees and sunny here. Enjoy what cruising time you have left. We still have a couple cruises to go this year. Laughlin economy run this month, about 125-150 miles included in 560 mile round trip getting there and back home. Then next month the all California meet approx. 525 miles round trip. I love to hear the motor singing down the highway it likes to go fast Sometimes I notice the speedo creeps up around 80 - 85 MPH.

Well, it is too chilly to work on the Hudson so my wife and I went to an estate auction in a small town an hour away and low and behold I found a pair of Hudson rocker panels standing in the corner of an old garage....still had a shipping tag on one. Taped to one rocker is a note: models 482, 484, 492,494,502,504. They're about 91" long, same as my 51 Hollywood and 50 convert. Before I try and sell them, maybe someone can give me more specifics on what years fit what as far as rocker panels are concerned. Sorry for straying off topic. Terry

the #'s you listed makes these for a senior car. Are they 4dr or 2 dr. rockers?. 4dr.rocker has 2 cups attached , one for the "A" pillar, and the other cup at the "B" pillar. When I refer to "cups" I am referring to where the leading edge of the doors pivot when opened and closed. A 2dr. rocker only has the frt. cup.
** - Another note, the easiest way to tell the difference from a SWB rocker and a LWB rocker is the swb has 3 holes where it attaches to the bottom of the frt. fender and the LWB has 4 holes. You can use these rockers on anything from '48-'53, just have to make small pieces of metal to cover the holes where the rocker trim attaches. The rectangular slots in them is designed for a special clip that retains the Commodore trim. These rockers will also work on a '51 Super, which used the wide, Commodore trim left over from the previous year. i hope this helps, d

Thanks, Doug. They are for a coup. Paid $10 a piece...could have waited until the next day( half price Sunday) and they'd have been $5 apiece but it was over an hour away. I'll keep them for now cause you never know.....Back to the original post, I went out and tinkered with the carbs today but didn't highway test the car...it's raining....again. I went through the whole sequence for installing and setting up the two carbs and I changed the back carb idle speed screw just a little. After it warmed up I tried what you recommended and pulled back on the throttle but nothing changed. I'll have to wait for better weather for a road test. Terry

Terry, remember, if the throttle plate on the frt. carb is cranked too far open, it causes the same symptom. Rough and/or erratic idle,hard to balance between the two carbs.,hesitation,etc,.. With the engine at normal operating temp., check and verify both choke flaps are all the way open and stay open. If they are NOT, adjust as needed before continuing. Make sure both springs are attached to the linkage rod and attached to the spring bracket at the base of each carb. , remove the pin in both the carb linkages ,not at the carb's ,but at the adjustable yoke end. ** - NOTE, I mention removing both linkages because if the attaching accel linkage is in a bind or not allowing the carbs to return to their base idles, it will hold the throttle plate open, even if you are cranking the screws to lower the RPM's. With the engine NOT running, screw the idle mixture screws in until it is lightly seated, turn each screw out 1.75 turns. This is a basic reference to begin from. Start the engine, turn the base idle screws to make the engine idle come down as far as possible and still allowing the engine to stay running.,making sure the throttle plates come closed as you reduce the idle screws. If they don't come closed on their own, investigate why?. It could be as simple as needing slightly more tension on the spring/sprgs. to return to base idle. Is there a gasket that is mis-aligned when mounting?.*** - I have seen carb mounting gaskets that are slightly too large, and cause interference with the throttle plate on the inside and not the outside, and very hard to diagnose. Now, try adjusting the idle mixture screws to maintain the best idle. Just remember how far you turn it in one direction from your original reference, in or out. First, slowly turn them in until it start to stumble, then count back out to your reference, then turn them out past the 1.75 reference to see where it runs the best. Once this is done, now the idle RPM's can be adjusted. Take note, if you have to crank one of the throttle base idle screws way up before you start getting results, there is probably a problem elsewhere that adjusting the carbs is NOT going to fix and will need to be further diagnosed. This might sound like a lot of work, but this procedure doesn't take very long

Thanks ,Doug. I've done everything you mentioned except for removing the pins on the yoke end when setting the base idle. I'll try that when the weather gets better. The problem here is, it starts and idles perfect when cold, fast idles nice and come down to a nice idle when blipping the throttle. It only shows up right after high speed driving and when I shut it off, I can immediately hit the starter button and bingo, perfect idle. I might add, that when restarting the car, it doesn't "turn over", it starts on the first plug it hits. I have my front carb choke set lighter (opens sooner) than the back but it literally fires up cold on the second or third plug it hits...doesn't stumble at all. With the front choke set like the back, I would have to slightly apply foot throttle to keep it from bumbling. I'm going to look closer at the vacuum advance and I still have not replaced the plug wires. I plan on driving the car before doing too much or I'll never know for sure what the cure was(is). Thanks again Terry

An update and new question. Found the vacuum chamber slowly leaks down when attached to a hand held vacuum pump and also shows signs of sticking as it runs out of vacuum from the pump. I have distributor IAT 4009A on the engine so what vacuum chamber would go on this distributor? E-Bay has three for sale right now, an IAT 2023d, an IAT 2023RN, and a Shurit V-114 which supposedly is the same as the 2023rn. The 308 is a late '55 engine without hydraulic lifters. Thanks Terry