I am looking at a used 9 horse long tail motor for my 1448 flat bottom. After looking around I have decided it is enough motor for my application. My question is if i want to upgrade to a bigger boat down the road would it be possible to replace the 9 horse with a bigger motor on the same frame? If so how big will that frame support? How much work goes into replacing it?

You just have to do your homework on crankshaft height, length, keyways, mounting circles, U-joints and prop sizes.

A motor with the same crank demensions will be the easiest to put on, but with time money and skill you could put a 35hp on that frame if you want too.

if you went 16-18 prob just crank side u joint yoke and prop. if its a briggs prob up to the 23hp without any mods. not sure on hondas.