Today I installed the heater A/C box in my 75. The problem I am having is connecting the box lines to the block. I was sent a box for a 77 and the lines are different lenghts and one will start but the other line will not start. I may pull the box and use the evaporator core from the 75 box. I thought the Mavs would be the same. Texasjack
Box Craig They ain't, the lower line is longer than the top one but the hole in the block is also deeper. I will probably pull the box out and install a new heater core and the evaporator form the 75. Texasjack