[Excaliber]

Prototype may be the key word there Jack.

Toms Motorsports have been running their small block FFR with spirals (no choice as per required DB levels at some tracks) and have met with some pretty good results in reducing DB without loosing much HP.

I loose close to a 100 horse with my STOCK side pipes all ready. Of course the bigger the engine, the more flow of cfm, in and out, the more significant the loss will be. A big inch engine is going to be hard to handle no matter what you do. I'm pretty sure I would lose less and be quiter with spirals.