Jack Sheeks also used ENYA 35s in some of his larger models.

ENYA engines do have noticeably more power than typical Fox 35s or modern alternatives, but they take a long time to break-in right, and as iron-in-steel engines, benefit from ample castor in the fuel (~25%). They don't wear out, though.

I saw Jack with his Hurri at a Nats. Think it had a modded Fox35. The old Fox is still a very useful engine, given a few touches and a decent break-in. But, you'll still have all that castor to get off the exterior... It CAN handle models up to 40+ oz or so, but with a bit more evident slowing in climbs and corners.

Enjoy!

\BEST\LOU