After re reading this, there are a few things I see. First, that^ is quite a bit of timing on a motor still cranking 160psi with exhaust work.
Second, if you know what to look for, a leak down may not be a big deal. But to someone who is just learning these things like your self, it is worth doing your first couple times. You said there was "No need" to do a leak down since you knew it needed to be rebuilt. But a leak down would show you exactley where the failure is from. You are doing all this top end work, did you do new crank seals as well? I couldn't begin to count how many buddy's bring me motors they say they just rebuilt everything twice and still have repeated failures. I throw the leak down on it and it's a crank seal. Funny part, typically the crank seal that's puking is the same one that there are failures on.