I have a 1979 f250 460, I am having problems advancing the timing around to where the marks will line up. I turn the distributor as far as I can until the vacum advance is all the way around against the water hose. Any info would be helpfull.

 

First of all, what do you consider the "marks lining up"? if youre sure that the timing needs to be that far advanced (the engine continues idling smoother and higher up till the point where the dist. stops) then you will need to pull the distributor out and set it back on the next tooth over. you will probably have to spin the pump shaft with a primer tool (or whatever you can get to fit in there) a small amount so that it will go back into the dist. in its new position. just one tooth over should do ya i would think. good luck.

 

I rotated the distributor one tooth over and it is idling good now. I am using a vacum gauge as well. I am getting a good constant reading of 19", but about every 5-20 seconds the engine stumbles and the vacum drops off for a couple of seconds. Is the stumble caused by the timing or by something else?

 

How many miles are on the motor? What kind of carb? What condition is the ignition system in? Is the motor at normal operating temperature? Is the motor responsive if you put a load on it? This will help determine what the problem is.

TBirdGuy