First of all welcome to the List!  Now on to your questions:

> i've found on a scrapyard an'90 5spd double cap vanagon, does the gearbox of
> that one fit on my caravelle?>> Not without some major modifications
> including shifting linkage (they changed the linkage between the diesel and
> the watercooled).  Also you would need to shorten the mount on the nose of
> the tranny for the longer 5-speed tranny.
>
> to put a 5spd on my 4spd 1.6l diesel caravelle makes any sense?>>  Not
> unless you are going to totally regear it to your diesel engine.  The
> waterboxer 5 speed would not compliment your diesel engine at all.  It
> would make you have no power at any speed (like you already have any to
> begin with:).  Hope this helps.  Maybe you could buy it anyway and sell it
> to some wealthy American list member?
>

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242