5.7 6.1 port differences

there were only 5.7 port and 6.1 ports from 03 to 08 they were the same on all years (per given motor) in 09 the ports of the 5.7 became the same as the 6.1. It is called the eagle motor. Due to port size and going to a closed chamber head the power was increased from 345 to 390hp. Bassically the 08 and older 5.7 had a rectangle ports and the 6.1 had a square port. Or vice versa (i can't remember off the top of my head, and I'm tired too so it could be flipped) then in 09 the ports became the same for 6.1 and 5.7. I hope my ramblings made sense to you.