What can cause a distributor to seize up?

possible causes may include:broken or chipped disributor shaft gear teeth;Hopefully no damage to the camshaft that drives the distributor,otherwise,replace the distributor and you should be fine.Remember to mark where the distributor meets the engine block both on the unit and the block,otherwise you may put it in wrong and will have issues.Also make sure to use proper grease to lubricate everything as needed.

it possible that you could have bent some valves this is a common issue with that engine, it all depends on how much money you want to spend.