Hi xRaINx. Welcome to iboats. It looks like 40 hp is the max, but I have a 20 hp on my 14' v-hull, tinny and that gets it on plane with ease. While you certainly could get a shinny new, 4-stroke motor, most of us like the old, vintage OMC motors from the mid 50's - mid 70's for their ease of availability and maintenance, low cost, reliability, and cool looks. A nice '57-'59 35 hp Johnson would be sweet. Here are some handy links when/if the time comes.