How much work to make a 2001 Sport Instrument Cluster fit a 98

[BBQ_HotDogs]

I know it has been done. I saw it in Tas98's truck and also ExRob's truck, but how? The dealer says it won't fit, that's fine. But why? They look exactly to be the exact same clusters except one has a white face with red needles and the other has a black face with white needles. And in ExRob's cardomain site, he says he had to do some special fitting to make it work, all I want to know is what? Can ANTONE help me on this?
Thanks in advance,
Ronnie

 

[BBQ_HotDogs]

OK, Tas98 PM'ed me and said it would fit except for the odometer. I would have to change that out with the original one. That's cool, want to keep honest miles anyway. But curiosity is killing me as to why? Why does the odometer have to be changed out? Is it larger or just fits differently or what? There is no actual cable anymore like the old days so that just makes me wonder, please help clear this old mind. The auction for the gauge cluster I am bidding on ends tomorrow night, Tuesday is the reason I am asking these questions now. It has the piece that shows the PRND21 in it where the others don't. If I don't win the auction on it, how much is that part from the dealer, anyone know?