From the 75 MPC (which explains the C9 substitution):
Part Number Dia 200 289 289 289 289 390 390 428
Part Number Dia base base GT comp GT350 base GT GT500
C7WY-5482-A 3/4 X X
C7WY-5482-C 7/8 X X
C9ZZ-5482-E X X X
C7WY-5482-B 3/4 X
The interesting thing is that the base 390 has a different bar than the base 289, yet is the same 3/4" diameter. Must be the shape?
But the GT 7/8" diameter bar is the same for 289 and 390. Go figure.
Also there is nothing specified for the 390 with competition handling, but that would be the same as the others I presume.
The C9ZZ-5482-E bar diameter was not specified.