I've always used drill motors in my project boats. You can find them in a 700 or 800 size cans. For a hull that big you will need 2 of them coupled to a geared down, single shaft running 12-20 NiMh cells depending on whether it is a 700 or 800 can. You should be able to run at least a 45mm prop or higher depending on prop drive type.

I'd recommend an ESC capable of 80A @ 16 cells - 19.2v or 80A @ 20 cells - 24v.

Any motor found in a car is not capable of high RPM. My blower motor sounds like it runs at no more than 5000 RPM. A drill motor is capable of over 20 000RPM.

Ryan