Do you have pictures of the pistons along with specs for comparison? I have always thought about upgrading pistons in the V8. Your information would help me some.
The 06+ has a double valve relief on the piston top while the early v8's do not. The early 05 that I own had a funny TRIPLE relief that I could not match with any other piston I could find. I actually don't have a picture of that because I ended up using the same piston with a new rod from an 03 truck.