David, the main thing that kills or severely shortens the life of these
engines is heat.  So, as Bulley has pointed out, you want all of your engine
cooling tin to be there and in good condition, along with the seals that go
in between the tin, and in the engine compartment.

The other thing to consider is don't overload or overstress the motor.  I
mean I had a friend with an aircooled Westie and he got a rebuilt motor from
AVP that was waranteed not to drop a valve seat and then he loads it up with
5 or 6 friends and all of thier stuff and even tows a small trailer behind
the thing on the way to the beach in North Carolina in the middle of the
summer and then complains when the motor overheats and drops a valve seat.
This is somehow AVP's fault :)
Just keep in mind your van isn't a F150 pickup.  Take it easy on hills and on
really hot days and you'll be fine.

But most of all, drive it, have fun, have adventures, after all that is whole
point isn't it?

Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242