3" Xpipe to 2.5" tail pipes?

I'm going to be running a 600+ hp stroker small block. Will I be alright with 3" x-pipe then after the mufflers run a 2.5" tail pipe? I'm only doing a offset springs but I still want to have the room to run the factory style tips and location. I may even run a dynomax bullet muffler as a resonator. I just don't want to cork the thing up.