It may be that the distributor is stuck in the block. Disconnect everything and squirt penetrating oil around the base, let is soak for a while, then see if you can move the distributor. You might have to keep up the penetrating oil routine for a while. Also, try moving the distributor when the engine is hot, if you haven't already tried that. If nothing else works, you might have success using a slide hammer with a yoke to fit around the distributor bowl and pulling it with the slide hammer. There are devices made for that, but they are not especially common. If you use a slide hammer, be careful not to break off the grease fitting on the side of distributor. Alternately, a strap wrench, along with penetrating oil, might give you enough leverage to turn the distributor and loosen it in the bore.
You likely have something else going on with the surging and hesitation, but you need to get the distributor situation resolved, too.
Harvester
