Those 380/360 had cams to get that 360/380HP number and still use stock rockers to keep cost down. Many customers bought them with "eyes bigger than their stomachs" and would try to tame them down putting dual planes or EFI.
NS1RM21 sold lots of them at Westoaks MP. And after talking with the customers would often suggest 300/320 horse was a better fit for them. But at end of the day customer is always right.