When I upgraded my 84 Westy to a 2.1 engine 11 years ago, I presented myself
with the same question.  I decided against it because:

1.  Had almost no 2.1 cooling components/hoses (only had the 2.1 longblock).
2.  The 1.9 system was in excellent shape
3.  The cost of converting to the 2.1 configuration was IMO stratospheric,
even at my shop cost.  I'm sure GoWesty gets their "pound of flesh" for this
procedure.

I have continued to use the 1.9 cooling configuration with my 2.1 for the
past 11 years with no ill effects or problems, with a stock 87c thermostat
and the gauge needle reads comfortably on the left edge of the LED.  It goes
up just a smidge when tackling a long grade up the hill (like LA's
Grapevine).   The only problem(s) I foresee will be replacing certain 1.9
style hoses which are no longer available.  Heck, some 2.1 hoses are
now becoming no longer available.
--
Jim Thompson
84 GL 1.9 "Gloria"
84 Westfalia 2.1 "Ole Putt"
73 K Ghia Coupe "Denise"
72 411 Station Wagon "Pug"
oldvolkshome@gmail.com
http://www.oldvolkshome.com
***********************************
On Mon, Jul 7, 2008 at 7:34 AM, Jamie Fitterer <fittdog8848@hotmail.com>
wrote:

> I am thinking about upgrading my coolant system on my 84 1.9L to the 86-91
> system.
>
> ANy thoughts on whether I should do this or not?  I see taht GoWesty does
> it on all their Vans and was thinking maybe it would be something good to do
> while I have Van in to get its Fuel lines replaced.