RE: Telemaster 40 engine?
It's a helicopter engine but should work. The heads on those were usually oversized for cooling. Just be careful with it. The head may cool off too much in flight. You may be able to get a standard head for it if it does.
I also would agree with the previous poster. A TT 46-pro would be a good choice for this plane. Good luck with it. The Telemaster is a fantastic trainer.
Mark Shuman