FWIW, the mileage may actually be pretty close to accurate. Most "Fire Trucks" rarely spent much time on the road. Much more idle time to make sure they were ready to roll when called for. Being used later to occasionally water down a track over 2 years wouldn't add much to the ticker either.
With your consideration to convert to either a rollback or ramp body truck, further discussion and conversations would probably be better posted in the
Big Bolts forum to get the best help and responses, especially considering your questions about changing/upgrading the driveline/suspension. Another alternative spot to consider may be the
HiPo Shop forum.
Good luck and looking forward to seeing more of your truck and the project as it progresses!
