I have a 98 150 that I messed up the spedometer in trying to put one of those gauge backgrounds in. I found one on ebay that has a tach and mine doesn't. If I plug the tach into my truck will it work? is the wiring there or do you have to rewire it? Another thing can the dealership change the milage on his cluster to match my truck? Experts out there let me know!!!!!!! thanks a bunch.