oil pressure

I'd stop running it until it's raod-worthy (sounds like it's not yet?) and give it a 100 miles of normal driving. See if it smokes less over time. I think it's ring-related, but give it a chance to clear up on it's own. If there is no improvement as you drive, you should do a leak down test to see the condition of the rings. Has this friend built an engine with KB hyper pistons before? There are special top-ring gap specifications.