Great thread. "2 C8H18 + 25 O2 → 16 CO2 + 18 H2O" Pretty cool when Chemistry = Stuff I have observed!
I put true duals on my C10 and have noticed it too tends to exhaust a lot of moisture when I first start it. Initially I was concerned about a blown head gasket. I keep a close eye on the oil (no signs of water) and on the radiator (no drop in antifreeze level).
Additionally the moisture in the exhaust that ends up on the concrete driveway evaporates away, no signs of antifreeze. I guess all's well that end's well?