I have a 69 westfalia van, no pop-top.  It has about 50k on an engine 
rebuild (170K total mileage).

In about the last 3k, it has begun to backfire occasionally on 
deceleration.

Is this indicative of any impending problems, or should I just relax and 
enjoy scaring the occasional pedestrian??

BTW, I've about given up flashing/waving at other VW's.  There are so 
many around here that I'm always reaching/waving - and the response is 
almost non-existant.