Time to address rebuilt engine oil consumption

I was hoping the pix would show a definate accumulation of oil deposits on one side only,, which would indicate the oil is coming from a direction,, mainly the intake runner,, which would mean a bad guide seal,, guide, or intake gskt leak..

But that final pic has tar all around the base,, which kinda makes me think a ring..

I'd yank the heads, looking for an obviuos intake gskt leak into a runner,,.

I'd move #4 & #6 pistons half way down the bores,, and fill all the cylinder full as possible with clean Varsol, and wait..

Cyls with poor rings will drain quickly,, Cyls with good rings,, may hold fluid overnite.. that'd be my test.. Rotate crank,, and re-fill cyls that didn't get much fluid the first time, noting suspect cyls... My bet is 4 and 6 drain quickly, others to varying time, with a few holding fluid indefinately...

there are several reasons a ring can break,, and you may have some..

hope it helps...