Combatpig,
I believe that SDP,
http://www.sdp-si.com/ has everything that you will need. Look at (timing belts) .080 (MXL) and .0816 (40 D.P.) they start at 1/8" wide. Even current helicopters that have a belt driven tail rotor, use this size timing belt. I was using this size belt on my machines back in 1970 and they were purchased from SDP. When used directly on the engine, a flywheel is required.
Gene Rock