The excrutiatingly slow fill seems to be part of the Syncro experience -
it's come up on the list at least once since I started reading in
January or so.  My wife has just started driving ours (6 months after we
bought it!) and noted this problem just tonight.

The MSDS 911 engine conversion includes a re-routed fuel filler that
Martin Schneider claims eliminates the problem as well as making room
for the oil tank.  Don't know if he sells the filler by itself.

ed
86 Syncro 2L