well for me i have a 01 5600. not sure bout the 4500, but i found a 271 out of a 04 with a 5600 and it is a direct replacment as far as the t-case bolting up. need to shorten rear driveshaft bout 3 inches. need to get a new rear yoke that fits a 271 what yoke u use depends on what u joints i want to use. u will need to clearence the tranny crossmember. a little re shaping of the cab floor. slide the gas tank back as far as it will go in the straps. make the shifter rod longer. now does your shifter stick come straight up a really short stick or come up at a angle from the rear to the front a longer stick. if yours is longer u will actually need to do a little more work.
