BLUE52,
I assume your rig is a truck, not a car, and that the 4 on the floor is actually a SM-420 which would be compound low, 2,3,4.
So you start out in 2nd, shift to 3rd then to 4th. This means every time you shift it puffs smoke!
If the smoke is blueish, not black, as everyone above has stated, it's burning oil.
From the dynamics that generate the smoke, it appears it would be guides..as everyone has agreed. The rings could be contributing to it somewhat.
The engine is telling you it is old, burns some oil and it might be time for a rebuild.
No machine shop would do just the guides without doing a complete valve job..then, what the heck, why not surface the head...it's out anyway.
So, you have just "rebuilt" the head. According to the Guru's, the new head will doom the old bottom..As Baldy said, drive it and enjoy it.
When you are using a quart of oil every 100 miles, and the cops are giving you tickets for smoking exhaust, think about a rebuilt engine.
If you dig working on these old rigs, drive yours the way it is, and start right now, finding another engine to rebuild at your leisure, and as your budget will allow.
Stuart
