63 is a good for an NSR. With ported barrels i woudl of thought maybe something over 65 but like discussed, every dyno is differnt.
Andy (nsr-world) made 62 i think last time we tested it. That was with the same kinda set up as you but without the port work. My MC18 63 without port work but after a whole lot of setting up.. 80 something runs infact. Bill Limbs MC21 made 65-66 with slightly modded exhaust ports. So Your 63 is right there.
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If I have to take the carbs off once more...