upgrade????
 

I have an old 12meter thats in great shape but thinking power upgrade is overdue. Currently has a couple 454s which im assuming have a little bit of work done being I was told they are rated at 500hp? Could be mistaking but pretty sure. whats a good way to go as far as power? Still has trs drives so not even sure they can handle any more? Not looking to go crazy, just a bit more of a punch while being reliable. Let me know what you guys think being most of you have lots of boating experience. Thanks!