Do you have big hills to climb to get the boat to water? If not, you should be OK, but I would also upgrade the radiator to a 3 core. The standard intake/header/exhaust/cam/oversize TB pieces usually get you another 10-20 hp collectively, and a comparable amount of torque. If you just do the exhaust and the cam you won't realize the full benefits of the cam change. In any event, the stock motor is probably strong enough, assuming it's in good condition. I would focus on the cooling and gearing...Oh, and you might want to look into getting a twin stick setup for your transfer case, so you can use 2wd L to crawl up the boat ramp after a day on the water. (I actually think pulling the boat back up the ramp will be the biggest challenge you'll face).

Good luck,

-Jeff