Glen
Several shops offer these planes with a bronze bearing 40, all of these engines seriously under power the craft and you will be lucky if you don't crash on takeoff.
I have a U.S. Aircore F-16 Falcon. It was originally powered by an O.S. 40 FP which was the recommended engine at my hobby shop. The plane weighed in at 7 pounds 4 ounces. This is a heavy plane. The engine could barely pull this jet off the ground.
I was mad, so I returned the O.S. 40 FP and bought an O.S. 91 FX. I Filled up the original mounting holes with JB weld epoxy and I drilled the wooden cartridge to fit the O.S. 91 FX. I also glued on some 1/2 inch steel reinforcement angles and cut them to 12 inches in length.
I drilled the landing nose gear block to 3/32 inch in order to accept the new dual strut nose gear. I raised the nose gear inorder to have clearance for the big propeller. Then I added 3 1/8 inch steel rods and glued them inside the fluted cuts in the stabilizer; I also placed 2 in the vertical fin.
The plane came in at 8 pounds 11 ounces. I finally went to the field, run in the engine 3 tanks of fuel. I then took off and WOW. What a ride. This plane really hauls with the 91 FX. It had unlimited vertical and was clocked in at 144 miles per hour straight and level. I am happy now.