Thought I'd share...
If your still looking for an engine, not sure if your interested in wrecking yard stuff, but I was at pick-n-Pull in Stockton today. They have a wrecked brown '86 with complete drivetrain, open-diff trans. I didn't check the price of the engines, but they're pretty cheap and guaranteed. I'm tempted to grab the trans as a backup since their price is only $87.00.
Someone already snagged the front suspension, rear is still there with 951 koni's.
It also has 3 phone dials on it, someone would have to drill out the locking lugs to get them, I think they're $22/ea with the tires.
It's in with the Mazda's, they always mistake them for RX7's there.