[shelbygt500]

Thanks, helpful. I wanna get to 550-600HP. Sounds like a fair amount of machining on the Shelby product will be necessary, and even then you might not get the flow and overall performance that you can get with another product. So you pay extra for the name and, in the interest of "correctness," lesser performance. If someone has machined Shelby heads in order to derive maximum, or at least improved, performance...I'd be interested in their comments on the outcome.