Heat system ?'s

My xj is an 88 witht he original heater core, I dont' think it's ever been flushed so I think that may be the start of my problems. Anyways getting right down into it. When I switch my xj to heat or bi-level, I get no heat at all coming out it's more like 60 degree air. and it does not blow out either it kinda leaks out slowly.

My main question is I have a chance to get all the parts blower motor, heater core, vacuum swtiches and all out of a 93 xj for real cheap. Will these parts work in mine if i swap out the entire system or choose just to flush the core then swap in the new blower motor?

thanks

Go cheap first,see what works and what don't.Back flush like there is no tomorrow,might even try 2 or 3 times(I did this)backflush the htr core by garden hose into the bottom fitting then into the top fitting,keep going back and forth till it runs clear.
Prestone makes an engine flush and there are several others out there that basicall all do the same thing.
Vacum lines check each and every one for cracks,lpaces where they have rubbed against the body or engine.The small plastic lines can be spliced with
5/32 ID gasline hose.However if a whole line needs to be replaced I would try to find some of the original if possible.