Here are a few pictures with dimensions.
Heater motor to mounting flange is 5 1/8" to 5 1/4"
pic 1 Kick panel to firewall heater motor cut out hole is 5 1/8" to 5 1/4"
pic 2 pic 3 pic 4 I suspect what LonnieC suggested that the portion of the heater that is beyond the
mounting flange (look at pic 1 the level is pushed up against it)
is maybe getting hung up and the flange is not seating tight against the kick panel.
Or maybe the truck has been in a accident at one time.
My truck has never had any factory heaters ever installed.
Sound deadening material still intact at firewall where heater core hoses pass through.
Disregard all the non-factory holes in my firewall someone before me installed an aftermarket heater.
Magic Air Thanks,
