I have a 396 in my 68 Camaro, just recently noticed a fine "mist" of some kind, on my rear bumper, especially after long drives. When I first start up the car, I see some condensation coming out of the tailpipes, but always assumed this was normal from just sitting for weeks at a time. I used to have the mufflers dumped behind the rear axle, and just recently had the tailpipes run right out of the back of the car, which is probably why now I'm noticing the "film" on the rear bumper. Car uses some water, but not much, maybe a gallon every couple hundred miles. What am I looking at here? Head gasket? Intake gasket? It's not isolated to one side either, there's an equal amount of film on both sides of the bumper, I've smelled it too, doesn't smell much like anti-freeze, or anything else for that matter? Could this me normal??? Ideas anyone?