I felt/feel the RP head with it's 2.75" of cross section & 245 runners was hurting TQ a bit, seemed little off what I'd have liked to see. Did pick up little later, but overall the head is a BIG head for a 4.07 bore 416, but power was good, TQ just suffered a little as I'd expect.

Here is is motor in same tune, 39 timing, Big tube dyno headers, just changed to Sunoco HCR+ race gas & a Box stock 1050 Quickfuel dominator for a quick glance to see what the fuel & carb change would do: