I'm doing some rough measuring... I don't think the Tri-State heater will fit entirely behind the firewall. In fact, since I'd like to use the main heat duct on the cabin side of the heater, I'm moving it into the engine compartment as far as I can without blocking the side ports.
Also, if you have a newer FFR, watch that vertical dash hoop brace. It effectively blocks the left duct if you don't move the heater box away from it a couple inches. Even at that, I'm not sure how I'm going to get a regular duct tube on it. I may have to fab a duct out of fiberglass to get around that brace. Not sure yet I'm just starting this step.
[ March 24, 2002: Message edited by: Advil ]