400EX Cylinder Head Identification

[mfr440]

What is the difference in these two cylinder heads? I didn't realize there was a change.

1999-2007: 12200-KCY-670

2008-2009: 12200-HN1-A70

Thanks!

[Stickman400]

If you notice on the '08+ head you can't order the spring and plunger for the decompressor on the cam. After '08 they removed that. Other than that they are the same exact head. Idk why they changed the entire part number just becasue they removed 2 parts.