3" or 2.5" Pipes?

My old engine was a dead ringer for yours with the exception of cam lift (mine was a .557") and TTi Headers. I ordered the 3" pipes all the way back thinking I'd likely want more horsepower in the future and, although I'm running a 360/380 crate magnum currently, I still expect to go bigger in the near future.
Go with the 3".