I have a 1988 351 V8. I don't drive the E-250 van much that it's installed in and have not ajusted the timing in years. A little while ago I wanted to check the timing and ajust it. I loosened the hold down bolt on the distributor but the thing will not turn. I have sprayed penitrating oil around it and even took a wrench to the shaft and tried to move it and no go!

Any suggestions? Since it's a van there is not much room under the hood to get at this thing.

 

These distributors can really get seized in, especially if they sit a lot. I'd check the timing and if it's okay, don't bother trying to unstick the distributor. You could even apply a squirt of transmission fluid to the joint and leave the hold down bolt loose, and see if it unsticks itself over time while driving. Just make sure you keep a wrench in the van.