Thank you for all the input, gentlemen. Here's the latest. Pulled the valve covers back off last week and started from scratch, at 1/4 turn. Fired it up, noisy as heck. Went back in, applied a full turn, fired it up, sounded great. Let it come up to temperature, still sounding great. Headed down the road and I was riding high - until the engine got good and hot. Then it started getting louder and louder. By the time I was back home we were right back where we started from.
Got on the phone with Edelbrock, because they built the motor (seriously - no kidding - long story). Anyway, they asked for all specs, what oil we're using (conventional, NAPA, 10w30), what break-in lube (CompCam additive). They asked if ends of pushrods are distorted (no). Asked if there is any metal in the bottom of the oil filter. Cut it apart with snips. There is metal there - trace amount of very tiny particles.
I reported all to Edelbrock, but no response yet. Communication with them is intermittent at best. I did not yet check the lifters per Gun Jam's advice. I figure Edelbrock will next have me pull the lifters, at which time we will hopefully be able to evaluate them. Did not closely eyeball the valve tips for wear pattern. Will do so.
That's it for now. Sure is frustrating. Note, reason Edelbrock got involved in rebuilding motor is because first time around the cam tore up all the pushrods. There's something weird going on here . . .