[DeltaMustang65]

Ok, this sounds fishy. You had the mufflers off and it wasn't loud enough? I had to drive around with open headers once with my little stock 289 and I let it coast to the muffler shop as much as possible because it was loud as hell. I think you should reconsider, louder isn't better. I guarantee that super loud exhaust will drive you up the wall sooner or later, not to mention give you permanent hearing damage. Just go for that nice throaty burble sound and you'll be fine.