Harold's F'ing me over - big time.

I spent several hours talking with a GM exhaust engineer and the guy took the picture of Harolds design and painstakingly plugged it into his simulator at the GM design center.....harolds design actually causes damage and based on the TRI Y the flow, mix & pull ( exhaust synergy ) whatever the hell that is, comes out to be below that of a standard 340 cast iron manifold in fact its worse that that OF A standard 318 cast manifold!!!
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just shows that engineers and computers can be wrong. I have personally felt the night and day difference between a 340 manifold and spitfire headers. The improovement was incredible when we bolted the header on. That engineer put some data in wrong. Is it a perfect design? I'm sure it isn't. But it does work and work pretty well in my opinion. A full length header I'm sure would still be better but spitfires do work quit nicely.