occasional misfire
 

Having some issues with my msd ignition system. Hoping some one will now what is the maximum end play in the distributor shaft,. I have ran this distributor for about five to ten years. I have .025 of a inch. I have a new one and it has very little. Changed plugs, wires, and carburetor and it still does it. Mostly at low rpm, below 2500, ordering a new cap and rotor. Runs ok when you are on it. Thanks in advance:(