E-1 vs. E-2 cylinder heads

[Enginerd]

Gents,

Can anyone tell me what the difference is between an E-1 and an E-2 cylinder head for the KX500?  My 95 K5 has an E-1 head, but I just saw a 92 K5 head that was an E-2 head.  I assumed that an E-2 head was a later casting update, but now I'm not so sure. 

Can anyone shed some light on the situation?

Thanks!

[sandblaster]

This question has come up before.
From my research 89-04 KX500 heads are the same.
P/N 11001-1288
Yes, some have the E-1 and others the E-2 numbers cast into the head.
However, I have held both side by side and can't see any physical difference.
I took a few basic measurements and can't find any differences.
It's possible it the different heads were made at two different facilities with the same specs (doubtful) or even at the same facility but with different casts (Duh).
I just can't find any other reason for the different cast marks.
Perhaps some K5 Guru with insider connections would know.....

[Motorrad]

I've gone as far as cutting them in half.   I can't tell any difference either

[sandblaster]

There you go, Motorrad has spoken.... 

[Enginerd]

OK.  Thanks for the info!