I understand that a 2 ton rearend shouldn't be allowed in the 2.6 class to most people out there, but honestly it doesn't add any power at all. It actually may take away power because of more rotating mass. We have tried countless times to get a D80 to last in a 2wd and its just not going to happen even with the best of the best parts inside it. All of the power and load is going to that one rearend on the 2wd's. A 4wd equals out the load enough so that the D-80 will last alot longer. Lynn's truck really isn't making the power it should either to really be that competitive in the 2.6 class (No offence Lynn). If it were making the power it should, we would be ripping out a D80 every pass.
We also have a class in KOTTPA called Modified stock 2wd. Its a gasser class that has trucks making anywhere from 700-850hp, limited to a 1 ton rearend and weighing 5200lbs. Just about all of those guys rip out a rearend once a month if not more. I just don't see a 2wd diesel getting a D80 to last half a season unless you could get the trucks down to 4500lbs or less and cutting the engines back to around 350-400hp.