After I got everything back together from the freeze plug ejection incident the car started overheating every time I drove it. It was also hesitating. Took it to a dyno tuner and they where totally baffled by both symptoms. At this point I was so frustrated that I just parked the car and went to Burning Man. Back now, of course, and I'm just going to yank the engine and take it to a local builder for a teardown and diagnosis. As background, i had this engine rebuilt about six or seven years ago and it has always been incredibly difficult to tune (and I do know what I'm doing).
At this point I firmly believe either the cam wasn't degreed correctly by the last builder or he lied about the CR and that's why I have such poor idle vacuum and it is so hard to tune. Also, I have no idea why it is overheating. So, it is probably easier and cheaper to take it out, tear it down, degree the cam during teardown to confirm installation, and do a straight rebuild with either a milder cam (probably 260h), or install this one correctly. Then I'll do initial tune on an engine dyno to be sure it runs correctly.
If it turns out there is something major like a cracked block or some expensive head damage I may just toss this and install a J20DET with a 5-speed and have something different.