Just my luck. I'm in the midst of diagnosing head gasket failure. Went to work last night, seen some smoke in the mirror and pulled over, smoke just a rolling (hasn't overheated at this point). Since I know the radiator isnt that great, i went ahead and turned the heat on full to get the heat out from the motor, and i got no heat! So I turn truck off, check the radiator, its low obviously, put in what coolant I had, half a jug maybe. Seen a lot of smoke come from the exhaust flange gasket, bolts were gone. weird but whatever. So i figure the smoke was coming from a toasty felpro gasket. took it to work, no overheating, came home, no overheating, still smoked. Picked up a new gasket put it on, still smoking. So....What Have I got so far.

Lots of white smoke indicating burning water.
no overheating. slightly went past the op temp but came back down to op temp.
Hesitation upon idle/take off. runs fine getting up to and at speed
Oil is NOT milky. However, I did see very small rubber pieces on the dipstick.

Whats next. Compression test. I will post results with-in the hour. Pretty discouraged at the moment though. Had it running great other than the low oil pressure problem. But I don't see the two being directly involved. However, while I was under the truck messing with the new flange gasket i did noticed some oil on the bell housing, not a lot like before the rear seal repair.