Latest update.I checked the plugs one at a time by removing the wire.No difference between each one.I tried backing off the timing back to stock setting and it ran worse.I think there has been some movement of the damper ring over the years and where it is set now using the vacuum gauge is pretty close to being only a little advanced from stock setting.I am going to have a borrowed compression gauge next week and I will see what that shows about engine condition.Anyone have any other suggestions on where to look for the problem?Question for Gary (55 Vicky).Do you have a PCV system installed on yours as I do?I just changed the valve to one for a 302 Ford.Didn't help my problem But but I am wondering if this system is causing my problem and his if he has one.Thanks

  

I had a pcv system, new carb has no port, so I'm running open line from valley pan to the air cleaner for venting. Back to pcv with the winter maintenance.

       

Gary, 55 Vicky, St. Germain, Wisconsin

 

If you’ve ruled out the ignition timing, I’ll suggest you revisit the idle mixture screws at the carb.  Experimenting with the idle mixture when the engine is hot is easy enough to try and gut feel says the engine is lean so opening up the idle mixture screws some more would be a starting point.  Are both screws turned out equally or are they staggered.  From the closed position, how many turns are each opened.

 

On the four barrel carbs, the rear float level is important as there is a fixed idle circuit on the secondary side of the carb that also adds fuel to the overall mixture.  Shooting some carb spray into the eight air bleeds located on the fronts and rears of the venturies is also worth a try.

 

I’ll also add that too wide a spark plug gap can also make for an intermittent miss at idle.  You can try 0.025” gaps at the plugs and see if that helps in the short term.

Lorena, Texas (South of Waco)

it almost sounds like a dripping carb . It doesnt take much to cause a rough idle . if you look down the throat of the carb at idle you might notice a slight drip that would definately cause a rough idle . It should not drip at all. Be sure to chech it at the correct idle speed. Good luck 

Frank 

Hello Ted! I tried a couple your suggestions.Plug gap at .028 was worse.Wouldn't run.Put it back to .036.Idle screws at 1 1/4 both the same.Readjusted valves again.A little better.I am going to do a compression test this week and see if there is not a mechanical problem like a valve going maybe.I have an accel points eliminator kit but not HEI .What is the effect of gapping the plugs wider say at .040? Thanks for your suggestions.

  

I think I have the answer to my problem.I did a compression test-hot with carb blocked open.Cylinder readings were all over the place.I have 4 at 60-75,1 at 100,and 3 at 80+-.When I added oil to the lower ones the pressure only increased by 10-15.The plugs are not oil fouled and I am not seeing any smoke out the back on acceleration.My guess is the heads need to be looked at.The way it runs at anything but idle I am surprised at these readings.Any other input from anyone.

  

Hi, If it does not burn oil then I would suspect that you cam has worn flat. Before you pull the heads get a dial gage on top of a couple of valves and check the lift. Go to Youtube and see if there isn`t a how to video. Pete

i second pete..that minor change with oil is not enough...you may just have a flat cam...

If it aint broke, lets modify it!

1962 Galaxie 500 Town Victoria 4dr. 292 with a nice mild cam.

Salinas California.

Thats something I had not considered(flat cam).This motor had been running for who knows how long with no oil from the rocker shaft to keep the lifters and cam lubed.I now have that problem solved but maybe too late.I can't find that video on Youtube.Anyone want to point me in that direction or explain how to check the cam? Thanks for the suggestions.Hey Gary(55 Vicky).Have you thought about doing a compression test on yours?The problem you are having sounds a lot like the one I am having.Plugs look normal but idle worsens as the motor heats up.Question regarding the dial indicator.If I get ahold of one with the "magnetic base" is that going to work on this application or is there a different mounting I need?I found a video explaining how to use the indicator just not sure what or where I should be measuring the camshaft.Thanks

  

Rocker arm oil does not oil the cam and lifters.  They are oiled by splash from the crankshaft/rods.

You could make a gauge to check your valve lifts, since a few thousands difference lobe to lobe wouldn't be that big a deal in this case.  A strip of metal, plastic, wood, with a notch to sit on the valve retainer and the end cut to length to touch the head surface would work.  Turn the engine until one valve is fully open, adjust the length of your "gauge", and check the rest of the valves at the fully open position.  Or use a dial caliper as a "depth gauge".

John - "The Hoosier Hurricane"