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On the exhaust side, the visual differences between the previous Pro 1 and the new Platinum iteration (front) are more obvious. The radically redesigned exhaust flange area is easier to cast than that on the old head, but this isn't an issue of mere expediency. "This new head can be ported to the point that it's like a race head," McAfee observes. "So we didn't want to limit people's choice of headers." Also note the difference in spark-plug location (arrow) compared to the older head.