04-05 heads, HP1-1 & HP1-2? Differences?

[lil_billy_300ex]

I just picked up a 04 450r. I noticed the cylinder head has a HP1-1 casted into, where my 05 has HP1-2 casted into it. Is there any differences? thanks

[R3Concepts]

No difference, just early vs later castings.

[lil_billy_300ex]

I noticed on the hp1-1 the date code on it is 2003. And the casting inside the ports is pretty rough. But I haven't looked at the 1-2 close enough to compare between the two.