RE: Dumas Chris-Craft 1940 Barrel Back
My experience with Trinity Monster Maxx motors (3 sets, in an E-Maxx) is that they are overpriced junk. They make good power for a very short time and then they are crap. They fry the comm's easily. I can just imagine in a closed hull with no cooling air and no cooling water that you cooked it in no time.
Get a Traxxas Titan motor if you want the same size motor to bolt in. It makes 98% of the power of the Monster Maxx (verified in side by side testing) and will last 1000 times longer. Costs 1/5 as much.
If you run a car motor direct drive in a boat, you must run a very small prop to allow the motor to rev up or otherwise you are just straining the motor and causing it to overheat.