my 77 18' has an older 120 omc, and it has ample power. my 75 18' has a 150 yamaha, and it has more than ample power. i would think a newer 115 would be a good choice. especially on a bracket. i would do away with the in floor live well and build one into the front of the console. i was going to do this on my rebuild but ended up using a newer mako console with a 20something gallon live well built in. my boat rides great when it's full. i also have a 12 gallon secondary well in the transom but i mostly just use it for a trash can
