Because this build includes a roller cam, Blueprint says there's no real break in period required except to run their break in oil for the 1st 2k miles. No need to keep it under X RPMs until Y miles, or hold it at a certain engine speed for a given period of time. It's basically already "broken in" when they prepped it for the engine dyno.
After I'd taken her out a few times for short trips here and there, and the initial thrill had worn off, I began to get critical. I came to realize there's some idle bugs to work out and Id thought at one point she had a vacuum leak somewhere because she would diesel on shut down.
Initially I'd thought the hardline for the trans modulator has gotten cracked - it was very (too) flexy when I was reinstalling the vacuum lines, and Id been worried that it had been flexed one too many times now. I cut away a bit of the hardline to eliminate the offending bend, and added more soft hose to connect it to the carb. I also replaced much of the remaining vacuum lines for good measure. None of this had a notable effect on the dieseling.
Turns out, I think the dieseling was due to having to adjust the idle up via the throttle stop to make her behave out in these streets. I think the true source of the issue is the torque converter however. Bear with me and my newb logic:
Because I havent increased the stall from the stock 1500ish RPMs, and she makes roughly 150% more torque, the TC never really lets go. Because it was never letting go, the RPMs were dragged down by the trans, and the engine would stall. I turned up the idle because she sounded like she was stalling from too low an idle. She was indeed stalling for that reason...but not because the throttle was closing too far as I'd first thought, it was because of the TC gripping all the time dragging down engine speed.
So my "fix" I now believe ultimately is the dieseling culprit. Because the idle was effectively too high, it would diesel on shutdown.
For now, I've tuned the idle back down, and am shutting her off in gear, and then shifting to park. A new-to-me, rebuilt GM stock TC, with the internals required for a 2400ish stall should be ready in about a week or so.