I'm attaching a post from Michael Hart (June 8th, 2009). Mike listed all
the bulbs in Westy with the LED equivalents and a source
[www.superbrightleds.com]. I have ordered from this company, the listed
bulbs from Mike's list. I'm very happy with the LEDs. No issues ordering
or with delivery.

About the LED colour, particularly white, to match incandescent bulbs
use the 'warm white' option. Normal LED white bulbs appear quite bluish.

Should anyone need more details drop me a note.

D

'86 Westy 

Mike's note ...

Most of this information was posted by others a few months ago, but I
thought I would post this 'complete' list based on my further research
and installation of LED bulbs in many places in my '87 Westy.
The only comprehensive vendor I have found is www.superbrightleds.com
The following information should make sense once you look at their site.

All are direct plug-ins, with the exception of the heater control LEDs,
which will require some dexterity with a soldering iron to assemble them
into the existing fittings

1). Instrument Cluster: Quantity: 4: Product: B8.3D-x Instrument LED
bulb $ 1.59 (each): Options: White B8.3D-W  (Blue & Red also available)
(Alternative: High powered version B8.3D-xHP $2.59 each) 2). Heater
controls: Quantity:  2: Product: 74-x Wedge Base LED bulb $ 1.19 (each):
Options: White 74-W 3). Interior light (above driver): 42mm festoon
bulb: Quantity: 1:Product: 4211-x6 LED Festoon bulb $ 3.70 (each):
Options: Natural White 4211-NW6 (Warm & Cool whites, Blue also
available)
(Alternative: you can also pick more powerful versions of the 42mm
festoon bulbs). I believe these are the size you also need for the
camper light over the stove (but I replaced mine with a Thinlight
fluorescent fitting a while back, so can't be sure).
4). Interior light (in dash above glove box): 30mm festoon bulb:
Quantity: 1: Product: 3022-x4 LED Festoon bulb $ 2.84 (each): Options:
Natural White 3022-NW4 (Warm & Cool whites, Blue also available) 5).
Exterior rear side marker lights: Quantity:2: Product: BA9s-x-x-12V Wide
Angle bulb $ 0.98 (each): Options: 120 Degree  Red BA9s-R-x-12V 

The end result: a bright white look (or blue or even red if you so
desire...) to your interior lights and what I would call a more 'modern'
look to your instrument panel (& better visibility). 
Hope these instructions are clear to you.

Mike,

'87 Westy