Hrm, could be, them Road Toad's are a breed to their own.......I would find a parts manual and get a part number or go direct and check with a manufacturer's website.
Alternately, get the one you have fixed at a shop and then install a reducer/splicer in the line to lessen the pressure in the heater core.
(I am currently installing these in mine since they are summer beasts and need for cabin heat is low).