My 340 is blowing blue smoke

Maybe, but a cylinder leakdown test can rule out rings as the problem. A good mechanic can read the pressure drop, if any, to give a better idea of what the situation is. Imo, only thing we can do here is give suggestions, without being there we can't really diagnose it. Hope this helps. Oh, I had a car that puffed smoke at start up that became worse over time. Performance was still there. But what started as a softball size ball of blue smoke became basketball size and bigger. Ended up going through a quart of oil each week. Didn't smoke until I let up on gas, but real bad when started and not when regular driving.