conversion from then to now

[willy]

Weight is very important, if you are re-powering a standard notched transom you can do a 200 two stroke, but in a four stroke I would stay with a 150 or 140. If they have a four stroke 200 that is close in weight to those you could do it, I don't know them well enough to say.
They used to measure HP at the crank on the outboards but have been measuring it at the prop for a long time now. A solid transom will handle 200 hp no problem, I think some were rated to 225.
Think weight more than just hp unless you are trying to grab two adults up skiing or something and need the extra low end torque anything above 150 is diminishing returns on these hulls in my opinion.