I have one. It was a Forestry Truck in the Sierras. I Have been comparing it to street modlels and the first thing I notice is that I have 6 leaves in the rear suspension and 3 in the front where as all the stock K5s I see have one less of each. I also have a PTO winch and no smog stuff on it. And it's smog legal in CA. (go figure) My question is this. Are there any hidden mods that I have yet to see that you know about? Like reinforcement of body panels and the like? Also I think it has a 3/4 ton rear end. It's a 12 bolt but the guy at the local driveline place said it has 3/4 ton hubs. (think he means brake hubs) But it's 6 lug wheels. Anyone know about this? Heard someone say something about "the elusive 12 bolt FF". (joke?) Take a look at what my truck looks like with 33s with Federal Stock Height. I think I can get 35's on there with a little trimming and no lift.