'66 bug or van engine with mechanical-advance-only distributor...

I have to set the points at .022" (instead of .016") to get a 50
degree dwell angle at 1500 rpm.  The reason I say "at 1500 rpm" is
that with this point setting, the dwell angle is 60 degrees at a low
idle.  In other words, my dwell angle isn't steady--it drops smoothly
by about 10 degrees as the engine speed increases from low idle.  

At a constant engine speed, the dwell angle is steady.  There doesn't
seem to be a huge amount of play in the end of the distributor shaft
when I wiggle it--I'd say at most 0.5 millimeter.

Are my distributor bushings worn? 

If so, is it better/simpler/cheaper to get a new distributor or
replace the bushings?

If I should get a new distributor, is the mechanical-advance-only type
preferable for this aging motor?

Thanks in advance.
- Robb
--
Zuk & Associates
ACCESS Database Specialists
phone: (604)721-2656    pager: 389-4922    fax: 477-6138
email: robb@islandnet.com      web: www.islandnet.com/~robb