OK, here's the specs for the unit:
Heat Output: 1000 to 3400 kcal/h (infinitely variable)
No exact size given, but from the photos and documents I've seen, it mounts to the underside of the package tray above the transmission.
I found a link to a site which has jpg's of the service manuals for all the VW gas heaters. It's listed under the Type IV, but I've seen references to it being installed in Beetles and Ghias.
Gas Heater Shop Manuals
Any additional info would be appreciated.
Thanks,
Doug