John, I like the Run side of the voltage reg; easy to piggy-back, and no doubt what's what. Plus I have some OEM-style connectors. I figure a 5A fuse like Robert says is wise.
Back in the day running the power from the fusebox, maybe the thing that saved me was (a) I almost never use the Acc key position or (b) I picked up the power from the On side of the fuse?
Thanks, guys.

For the record, the repro in-dash tach is no more accurate than they were back in the day, it's more entertainment than factual.