Is it possible? 13B to 20B ??
 

I know almost nothing of mechanics (well wait, I know a little bit, but I'm nowhere near a guru) - but I'm wondering if it's possible to stick a 20B into a 2nd gen RX-7 ... I mean, I wouldn't doubt that it's been done before... wouldn't that third rotor just be heavenly? Anyway, anyone's looked into it and would like to share a little bit of knowledge with a new RX-7 owner who's very interested in the rotary engines?

sure, just have around $10-20k usd on hand.... and find someone who really knows what they are doing... it's not cheap or easy!!

That expensive???
Holy crap, you'd almost be better off building your own damn 3rd rotor...

A used 20B engine is only about $4,000 USD. The rest of the cost is for the custom engine mounts, flywheel, aftermarket EMS, aftermarket ignition, etc. Yes, it would cost you about $10-20K USD to do it yourself, but you can have a race shop (Pettit, PFS, etc.) do it for $30-50K USD, depending on the options.

Here is a link on the basic conversion considerations:
http://www.se-rx7.com/20b/

And here is a link of some completed 20B RX-7's:
http://www.3rotor.com/chito.htm
http://www.cris.com/~Asam/20B.html
http://www.mariahmotorsports.com/
http://www.pettitracing.com/