Yes, it's a 350 manifold with the holes re-drilled to mount on our engine. It changes the length of the runners to shift the powerband downwards a little, and seems to make a net gain over the whole range in trade for a little HP loss at the peak RPMs. The main point of debate is that most of those gain charts are swapping manifolds on a car without changing the tune. I think the few that have tried tuning the ECU with the old manifold and then tuning with the new see very little net gain. In other words, the ECU fine-tuning and the manifold seem to overlap on gains considerably. Not enough data to say for sure though.
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