I may be wrong but doesn't that look like late 340 HP specs? When the 318 was like 180 Horse the 340 was rated at 235 (the late 60s 318 spec...) you know basically smogger 340 Horsepower.
You talking about my curve? That model was run with the parasitics that a later engine would have been tested to like waterpump, etc so it is a hybrid curve... early specs but running the test more like they had to in the later years (along with the lower performance specs of the early 70's). It is 10.5:1, 2.02 valves with measured flow data.