I am thinking about building a belt driven long tail without clutch. What size timing pulley would you use on motor and shaft that goes to prop. Looks like you would go as small as possible. The gear ratio is something else I am thinking about, would make a difference on prop size. Any info would be nice.

Think 1.5:1 like a surface drive. The size isn't a huge issue just think compact enough for your application and get your ratio right. Prop will have to be larger to gain anything with the increase in torque.

lookin at 32 tooth on motor and 44 on prop shaft. Have a 22 hp lifan engine that I will start with. Using 9/5 prop on regular LT with this motor, does good. What do you think I will have to go up to on the prop? Reason I am doing this is duck lease is high and dry and dont see it getting any better. need something to do constructive to stay out of beer joints.