I bought some 2" flexible duct hose and some nice round air vents. I mounted them under the dash on driver and pass side. They are the type that swivel 360 degrees and you can aim them into your lap or onto your feet. Feels real nice in the winter. If the FFR heater only has one outlet, just buy a tee and run both lines off of it. I know some people have linked them to the fresh air vents but unless you still put some vents that allow you to aim the air, I don't think it would work as well.
FFR4356, 351W stroked to 393, Carb,Tremec TKO midshift,IRS, PinDrive,3.55s,FR 15:1,PBR Brakes,Team III Wheels - Paint by NCPainter