I've replaced several heater cores in 4 cyl Rangers and it is a all day job (4-6 hours). You have to remove the dash, right side inner fender wall and HVAC blower box. It's not that hard but very time consuming. Don't worry about the dash it's only held on by about 8 bolts, two by each door and a few under the windshield. let me know if you want to try it and i'll give you some pointers.