Check out
www.car-part.com. They don't list your province on there, and I don't know enough about RX-7's to decide if you have a 12A or 13B engine, but just about any part you could need is listed on there.
I saw a RX-7 w/ a SBC in it at the drag strip a few weeks ago. Unfortunately, the guy seemed to be having troubles or he was packing up and I didn't get to see him run. He fired it up as we were walking up and I just said to the guy, "That's not a stock motor is it?" He just grinned and said "Nope." Wicked looking & sounding car.