One thing to watch out for is with hybrid ceramic bearings (steel races, ceramic balls) the steel races can wear, score and pit faster due to the extra hard ceramic balls. This seems to be more in tune with maintenance where the bearings are exposed to things that lead to corrosion occurring.
So if you are using a ceramic hybrid bearing set, the bearings aren't going to last longer than a all steel bearing set. the steel races will be the weak point for corrosion and wear. The bicycle people have run into problems where the bearing races are wearing out faster with ceramic hybrid bearings, but this appears to be due to maintenance and not keep the bearings free from moisture and keeping them clean as much as possible.

I might give the ceramic bearings a try one day. but heck, they cost as much or more than the engine I would want to put them in. so i still do not find it all that worthwhile yet. But if I got back into pylon racing or something where every RPM counts, it might be worth it. But like Daven stated, I don't think you can measure the improvement in performance with a engine.



10quicksport, consideirng how many parts one can trash in changing the port timing and making other mods along the way, I would just get a Nelson engine to start with. Then you don't have to destroy a bunch of parts trying to get that extra bit of performance of the engine.
The typical method is to take a part and machine a little off of it, then assemble the engine and test, then disassemble the engine, machine a little more off the part and repeat until you go too far, then chunk the bad part and machine a new part to the point where you got your best performance.
Then with ABC cylinder sleeves, you can't machine anything off the ports without risking the chrome being damaged, about all one can do is maybe using a shim to raise the cylinder a teensy bit and see what happens. although some guys have been known to machine their own sleeves and somehow get them chromed to testing with.