One more question: I know that the 53's haven't been produced since the late 90's, but the reason I keep refering (or comparing) the 53 to the 63S is because my cousin has a few 53's and he is VERY pleased with them. So from his knowledge on the 53's I have a "baseline" to judge the information given here about the 63S against.

That out of the way.....my next (hopefully last) question is about carburetion between the two (53 and 63S) I know from reading about them, that the regulator has been repositioned to run cooler. But is the carb setup, design, or "calibration" etc. the same?

I'm sorry I ask so many questions about this.....but I'm trying to go into "uncharted waters" with this project of mine, and would like to know all the potential drawbacks before I drop $500 on a pair of 63S's (Literally water....I need a large sized 4-stroke for a twin engine deep-vee boat I'm building. But no company offers one anymore, so I plan to convert the 63S hopefully)

Thanks Again