I've started into a project to replace the heater with a larger one. The first phase of getting it in place and running has been done.
The first phase has a little write-up here: http://rovers.red90.ca/Heater/
I've also started reworking the dash side to free up the air flow. I'm waiting for a couple of other items to arrive before I get the details written up and the testing done on that part.
Heat output is fantastic.
If you have any questions let me know. I've done a lot of searching on available heaters and other parts to get to this point.