Are the spark plugs clean? Have you tried Smoke Fix type engine oil additives? Mostly snake oil, but it might reduce oil burning a bit.

You could replace your valve seals with Vitton type.

I have a Jeep CJ 5 with Factory AMC 304 V8. Had the heads rebuilt at a local shop. A year later the engine smoked quite a bit. Initially thought it need a shortblock rebuild. Rolled the dice and replaced the valve stem seals with Vitton type, and ALL the smoking went away. I was amazed.

I used an on-head type valve spring compressor and compressed air with a fitting to hold the valves shut. It was like a magic cure. It is still a clean burning engine now five years later.

Do you have a Pan Evac? Sort of a poor mans crankcase vacuum pump. It can reduce blow-by and improve ring sealing by reducing internal crankcase pressure. It is fairly cheap to do. Just weld a 1/2-inch pipe into the header collector, thread on an exhaust check valve, connect hose from check valve to a breather fitting in the valve cover. I currently have Pan Evacs on my '79 Jeep and my '71 Charger.