1988 R2/4J heads will fit, and you may get away with an 1987 MC16 head, although it will take a little creative plumbing as the outlet differs to the MC18.
Using an MC16 head may also effect the compression ratio.
Only 87-89 heads share the same patterns. No other models share heads with NSR250s.
_________________
Andy.
NSR-WORLD.COM
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