Jason,

Instead of wasting your money on a 2.1 L ( which has problems of it's
own....rods and conversion costs).

Why not try this first.....Change the ignition timing of your van from 5
degrees after top dead center to either zero
degrees top dead center or 5 degrees BEFORE top dead center. You will get
better bottom end torque and the
engine will pull through the gears ( especially third) much easier. Start
off at TDC, see how you like it.  You can stay there or advance it another 5
degrees.

I too own an 85' Westy with a stock 1.9 liter motor.  all original miles and
no problems.  I have had the timing like this for six years now and have had
no problems. You will love the increased power and drivability by changing
your timing.
Of course when smog ck time comes you revert back to factory settings to
pass, and then advance the timing for added performance.

You will find that changing the timing will give you the power you are
looking for for no cost( of course you need
a timing light, with an advance dial, preferrably) or a friend that will
help you.

Good luck,  email me for any questions

Malibu Tony  85' Westy  1.9 L      8 degrees BTDC  130k on orig eng