2001 vs. 2002 LS6 head
 

What is the difference between a 2001 and 2002+ LS6 (243 casting) head ?

I think the springs are different. Did the light weight valves come out in 2002? Any flow differences?

Thanks.

You are right, the light weight weight valves were first used on 02 LS6 heads. A more aggressive cam was also used on the 02 LS6, I am not positive but I think the 02 springs are also different than the 01s. I believe 01 & 02 heads flow the same.

As the owner of an '01 I can tell you they don't flow the same. The '02 heads are slightly better. If you want to upgrade I wouldn't worry about the minor difference you'd get from the '02 vs. the '01, but if you are looking to upgrade from LS1's I would go for the '02+.