Don't add oil to the cylinders. You will just be hindering your progress. Do another leak down test at 100psi and report back with results. While doing the test, check for leakage from the crankcase and also around the valves and in the water jacket. You can use a lit cigarette around the valve springs to find air escaping. Determine where the source of the leakage is. That will narrow it down. If it won't register on the second gauge when you put air to it, someone forgot to put the pistons in so you should go ahead and pull the heads.
cast or molly? did you install top ring and second ring dot up or down? if the bevel is is up compression will push past compression rings...just say'n molly rings are harder and take forever to seat don't like them myself but just my opinion
Totally untrue when the cylinders are honed properly and engine is assembled with proper lubes. (not atf,gear lube,50w,synthetics) Tony
I have to agee with Goagroper02 on the moly rings. They seat and work great in a fresh bore. It's on older engines that you just do a rering job on that moly rings sometimes give trouble. I'm thinking wrong rings, wrong size rings or improperly installed rings. The amount of blow by you are getting is more like an engine that is due for a rebuild than one that has just been rebuilt.
If it is leaking that bad, you don't need guages to tell it needs to come apart. While I agree that improper crankcase venting will cause oil to blow out, the fact that it is leaking past the rings that badly indicates you need to pull it down and figure out WTF happened. My bet is either upside down or broken rings. Sorry JMO.
I am just putting the motor back together had it honed and put new rings in everything else looked pretty good. Just figured the rings never had a chance to seat running the synthetic oil
if it was me, id get ahold of the machine shop that built the motor. a lot of shops i know hate when people bring back motors they've pulled apart or messed with.