Well, it probably can run it, but it might bog down fairly easily. 60" is max recommended size for good reason. Even though a B2650 also has 26hp like a B2601, it has a bigger engine, runs lower rpm's but has more torque, that's why that 26hp tractor(B2650) is rated for a 72" but the B2601 isn't. It might work if you mow regularly and don't let the grass get like a foot long or more. Also maybe drive a little slower to give time for the mower to do it's work. Another thing to consider is weight, how much does it weigh? You can only hang so much weight off the 3ph, too. Follow the owner's manual. It lists implement sizes.
