slant six help needed, burning oil

Most likely something in what you did; the rings failing just sitting doesn't make sense.

First make sure it is oil smoke; what color is it, like a blue-ish-white, and does it smell like burnt oil? Or is it white, or a sweet smell like antifreeze? ? With that much smoke and if it IS oil, you should be able to pull the plugs and find oil on some or all plugs, you might have to run it a while.

When you do the compression test, take a reading once on each cylinder and then repeat on that cylinder. If you find any low, then put a teaspoon full of oil in the cylinder, turn it over a few times, and then take another reading on that cylinder. If you have bad rings, the oil you put in the cylinder will tend to temporaily seal the rings and give higher reading. It is not a foolproof way of finding if the rings are worn in a cylinder (if the oil rings are really bad, then the added oil will make less difference), but it's a reasonably realible test.

Check the diaphragm on the vaccum advance dashpot as you check everything, to make sure it is not open and sucking in oil that way.