Actually the dual pattern cam is exactly what a weak exhaust needs. It allows the exhaust valve to open slightly before it would otherwise and stay open longer to help make up for the small valve and port. The cam can compensate for the small ports and valves if it is designed properly. They can be a bit harder to dial in but they are worth it.

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Paul
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retired mechanic after 35 years
specialized in Holley carbs and Ford Automatic Transmissions