Previous owner damages his credibility by claiming that 411 is a Porsche;
this ancient confusion is based on fact that VW 41x, VW Vanagon aircooled,
and Porsche 914 used similar engines.  Probably what he is telling you is
that the 82 Vanagon has an engine from the 70's, rebuilt to some extent.

Price of such a van depends heavily on rust/dent condition of body; I paid
$1600 for an 81 in NJ, where rustlessness is harder to find than in 
Florida.  Maybe you should look for another watercooled Vgon, so you could
use your current doorstop for parts?  Or are you through with watercooled
Vgons?
B.
Wm Kennedy
kennedy@admin.njit.edu