Next I did a trial fitment of the new early model Scout II heater core. I unscrewed the front ( facing truck grill) core heater box cover. If you decide to do this heater modification, you'll have to clearance the back (firewall) side of the heater box as the core tank won' fit into the slot. It's wider, maybe about a 1/2". I chose to cut off the indentation cover on the backside of the heater box to make intial rom. I'll modify the piece I cut off or make a new one and weld it in. Also, in lieu of the screws that were holding pieces in place, I'll probable weld where I can and rivnut things like the heater motor flange, resistor.