Brettinator

the Subject says it all. I am confident I have the clearance based on some measurements and a damn good muffler man who has done it on the fbody cars. But my question is will I gain or lose any amount of hp or just the sweet sound? I'll be running JetHot longtubes and these will be placed just aft of the collectors full 3" cutouts on both sides. I'm not worried about the noise because I'm sure I'll enjoy it at the track, and I've heard Longtubes with open Borla and love it I just want to save my 60 bucks for (2) exhaust cutouts if it's no performance gain.