Update:
Car passed an emissions test.
Coolant seals finally gave up the ghost.
I'm afraid the old engine won't have many useful parts in it, but don't have the free cash to spend on a Mazda reman.
Pulled the engine out a week or two ago, this is probably the biggest car project I've taken on so far. I'm going to try my luck with a used engine from Japan.
Trying hard to avoid doing too many 'while you're in there' projects this time, we'll see how that goes...
right now I'm very tempted to remove the power steering rack and modify it as shown here (guys on another RX-7 forum claim that our rack is nearly identical):
http://flyinmiata.com/tech/depower.php?x=1