I used the factory supplied mounts. I dry fitted the cowl and used a ruler to measure from the firewall to the end of the cowling to establish where I needed to mount the engine to ensure proper clearance for the rear of the prop spinner. Then I tested fitted the engine to get the right measurement. Once that was established correctly, I added about 1/4 inch for good measure and marked my mounting holes on the motor mount. Drilled my holes and mounted the engine. Measure three times to make sure everything is right before you drill the first hole. Plenty of room left on the mounting beams even with a Saito .65.