i have a 1996 cavilier 2.2 that now has a 2001 2.2 with the 96 head and oil pan. im having a problem with valves that will rattle when under load has anyone had a problem like this.

 

Valves rattle under load? Valves have nothing to do with load. They just open and close, regardless of load.
I do not know what's the difference between those heads, but my first guess would be the old head combined with new block is resulting in higher compression ratio, what you hear is detonation.