You won't hurt it a bit. I've never liked the strap type mounts anyway. In an environment where the surface is getting doused with oil and high frequency vibration is constant, friction isn't very reliable. If you have bolts running through those holes though, the engine won't go anywhere. Do be sure that the holes won't be right at the edge and tap them for threads. A shot of blue loctite will keep the oil from penetrating the threads and letting the screws vibrate loose.