The truck is an early M35A2 with a non turbo multi-fuel engine and constant 6 wheel drive. Multi fuel meaning you can run it on gas or diesel or a mixture of both. Mine has only been run on diesel and I have no idea how they run on anything else. 45 MPH is about tops for this baby although I have had it up to about 54 a couple of times. 145 snarling horsepower moves this overloaded unit around like a snail. The truck is a 2.5 ton and for some reason they mounted this 8000 pound unit on it. I had the pleasure of driving this home from where I bought it, a distance of roughly 1000 miles. It was during a heavy winter storm and with only a $5.00 tarp roped on for a top. Needless to say it was a long, slow, cold, lonely trip. The purification unit I know very little about and is so clean and complete I don't want too screw with it. I hoping to sell it either to a collector who will keep it this nice or a small water system that can use it for emergencys.