I am in the process of installing a Propex in my 89 Westy.  I was planning on doing the install in the bottom of the closet, but now that I have the closet out, which is major with AC, I am concerned about this location.  If the unit needs to be serviced it would require removing everything to get the closet out.  I would like to keep the rear heater and it looks like the Propex would fit mounted on the top of the rear heater enclosure.  The air intake and exhaust could exit through the rear firewall and clear the blower housing and hoses.  My question is does the Propex have to be mounted with the intake and exhaust exiting the sheet metal of the van, or could they penetrate the rear heater enclosure and exit from within.  I image the exhaust pipe gets hot, but how hot.  I could cover the heater enclosure with a sheet of aluminum to provide some insulation.  Does anyone know if this has been done.  I have only seen under seat installs where the rear heater has been removed.

Thanks,
Finn in Taos NM
87 Westy Pooh
89 Westy Roo