First thing is an oil pressure check. Smoke out the left bank (no cross over pipe) is a sign of bad valve seals or guides on that bank. Normally the right bank is not far behind. Knocking is a bad thing. Hard to mask at a hot idle even with heavy oil.
At the same time, I have calmed some smoke down by replacing the valve seals. Certainly not a new motor, but smoke is greatly reduced. You can do this without removing the heads. Need an L-bar valve spring compressor and a fitting for an air compressor to hold the valves open on each cylinder as you replace them. Screws in the sparkplug hole and uses air pressure to hold the valves up while you replace the seals. Not hard to do. You can extend an old engine for a couple of easy cruise night years and use the worn engine as it smokes little.
If oil pressure is low and you get some knocking, then an oil additive may help. Not a new engine, but at least you can enjoy until you save up for a rebuild. Baby it.
Rob
