Guy's i,ve been building m715's for about 17 yrs now and i just pulled a underdash artic heater assy and it has the biggest heater core i,ve ever seen in a stock m715 heater. This thing is huge.... It measures 8" x 9 1/2" x 3" thick and is 3 cores deep, the tubes are 1" wide .it has the provision for the 2 1/2" defroster hose hookup on top of it too... You talk about putting out some heat this thing i bet will run you out of the cab even with a soft top !!!! Doing a 100% resto on the entire assy. Also gonna convert the motor over to 12 volt. This is the nicest one i've ever seen. I was going to sell it but this is going in my personal truck when finished 4 sure. Check out this heater core.
Ps. Sorry about the caps but eyes are blurie tonight.