White smoke at start up

Have a 98' 3/4 ton 5.7 liter with 161k on it
started up today 6-11 has only sat for a couple of days cloud of white smoke when started first time it have ever smoked
What could be the cause rings, valves or just mortor getting worn ? I use this tuck to pull a 5th wheel do all maintenance myself oil change every 5k and kept up with trans maintenance also did a tune up at 102k also has been a very good truck just would luv to find out what is causing the white smoke !!

Are you sure it's white and not a light blue.....I don't know about the white smoke, but if it is light blue, it could be the valve seals. Small Block Chevy's are infamous for this. Both mine do it. My 88 does it everytime it starts, even if it has only been turned off for 10 minutes. My 96 does it only if it has set for a few days.

SO are you using any oil inbetween changes more than a quart, It could of just been steam if it was cool and humid that morning. Dont worry about it even if it is alittle oil smoke they all do it eventually and can do it for a hundred thousand miles.

THX i use a quart every 5k so i guess that's not bad being the truck gets used as a truck and not as a car most people use them for