Hi Paul
as i understand it:
Engine Numbers:
364- <20000 =73
364- >20000 =74
Close match and part numbers:
73 MX250
363-18511-00-00 FORK, SHIFT 1
75 DT250
Shifter - 1 - 250 B-C
363-18511-00-00 FORK, SHIFT 1
Thats about the closest I got.
Are you sure it is 364?
Recheck the numbers from the source??