Again, if it isn't smoking out the headers, oil isn't getting past the oil ring, or second ring. If it is smoking and "huffing" out the valve covers/breathers, that's cylinder pressure in the pan, and it may not show up on a compression test or a leak down. But it WILL show up on the dyno, or in the car, with a Dwyer gauge on the breather. If you don't have access to a dyno (an 8 hour drive to get on a dyno is a "no brainer", these days there is no substitute for a dyno for a race engine) you can test it in an automatic car, with two people.
If you have any sort of gapless ring, a leak down test can lie to you.