Yes sorry I am talking about the choke plate. I think I sortof fixed that problem. When I close the plate it runs better. But I believe that was because My idle mixture screws were in too far. So I had little gas and when I created little air through the plate it ran better, which makes sense. So I unscrewed both idle mixture screws about 1.5 turns and I was able to leave the plate open.

That also allowed me to put the car in gear. Whenever I put the car in gear it would die. After I adjusted the screws I could put it in gear without it dying.

The car was still running rough as of yesterday afternoon. I adjusted the valves last night and I will run it in the next hour or so.

 

When I first tried to start it this morning I could tell the valves were too tight. So I loosened them all a tad and left the valve covers off so I could adjust them more. I got the car to run and idle pretty well soon after that although when I revved up the engine it would bog down. So I tried adjusting the valves more while the car was running and long story short it made the idle worse but was able to rev up in the end. I guess there is a happy medium somewhere.

These rockers are crap though I think the area that hits the pushrods does not have a clean surface.

I adjusted the valves with the engine running by unscrewing the nuts until I heard them start tapping, then screwed them in until they stopped tapping, then screwed them in an additional 1/2 turn. Is that the correct way to do it? When the car is off I can still move the rockers side to side a little. That seems too loose to me.

 

Reviving an older thread here. I wonder what the outcome was? I was having the EXACT same issue with my '68 289 this week. I could not get the car to idle.......I advanced the idle screw on the throttle linkage until the car would idle, albeit a fast idle, but as soon as I would so much as touch the throttle the car would try to idle down and instantly go dead. I noticed the lean arrows on the automatic choke housing and proceeded to turn the plastic housing. (Did not know you could do this). I then alternated the housing adjustment with the idle screw until I could blip the throttle to idle down and the choke would catch it and idle the car back up and keep it running. It seems to idle higher than it should, but at least it's running!! Starts really well now too!!

 

Is it a bought rebuilt carburetor? I know we had the same sort of problem when we bought a rebuilt carburetor from a prominent mustang parts supplier. Turns out it was corroded from sitting on a shelf after being rebuilt.