Dustin,

I'd recommend to start building the plane.  If scratch building, start on wings, then on fuselage.    You'll have a  few years to think about what engine to use during this process.  13B - Normal porting.  180hp which is good for a Bearhawk
13B - Peripheral Port.  250hp  which is excellent.
20B - w/ normal porting.  300hp?   Initial Engine cost a little more expensive, but very doable as most rebuild parts will come from the 13B.

I'm thinking of 13B with normal porting, then a peripheral port.   Both engines being near identical for FWF installations, so conversion is not that difficult.  Goal is to get flying, get everything debugged, size radiators for 40% larger than needed (so when HP is increased, they should remain the same for oil and water cooling).

Do you have plans on putting it on floats?  I.e. I can see the increase hp of the 20B, but for hp/weight trade off on a Peripheral Port 13B it gives a nice sweet spot of decent hp with less weight.

Elden Yates built the first Rotary Powered Bearhawk, he had it for sale on Barnstormers, but never did see a full report on his installation. Often when planes are resold, they are harder to sell unless fitted with an aircraft engine.  Just the way it it (Tom Yoehman never did sell his V6 Ford Powered Bearhawk, until he removed the engine and installed a good - but used 0-360 with fixed prop... sold a few weeks later).  My goal is to build "simple, but light".   Hence engine choice, basic panel, 13B, fixed prop.   I'll go with Dual Batteries, but other than than nothing too fancy (single alternator, etc).  Nothing to show on the engine, but firewall locations (remember that 6 degree set back for the firewall!) and the Mount I'm planning on using. You can find cheap rusty cores when you go to mock up the engine mount.  I need the PSRU for nose, cowling, but lots to do before I get to that so no rush.

http://www.mykitlog.com/twalter

Tom Walter
Bearhawk QB#59