Fairly new to me '65 4 door with B18.
Engine idles & runs smoothly but has begun to exhaust blue smoke.
Replaced valve stem seals (which were incredibly hardened, but not broken). No help there.
There is no blow-by - it's all coming out the tailpipe.
My deduction is that the oil is getting past the oil rings and being burned and exhausted. Prior experience with bad rings has been crankcase pressure pushing exhaust past the brings (blow-by), and oil vapor up through the valve cover and hose into the front oil filter which then dripped oil onto the pass side suspension, etc. That is not happening in this situation.

I did a compression test dry
front to back:
140
155
150
145

Then did leak-down test
60%
45%
40%
50%

Then did compression test with oil in the cylinders
155
170
170
160

Any ideas about the cause and remedy?
I added some Lucas heavy duty oil stabilizer to thicken oil with the hope that less would be drawn up to the top end. Little to no effect.

thanks