Have any of you guys swapped engines on older mowers? I have an older bobcat that I'm thinking of bringing in on more cutting. Currently it has a 14hp single cylinder. It still runs pretty good, but bogs to easy in thicker stuff. I would like to upgrade to V-twin 15 or 17hp. Have any of you guys done this or tried to do this? Does the rest of the mower hold up to the power increase?