The marked up chart below sheds some more light on the situation.
I've add the blue line to the chart. The blue line shows what Graves was getting before the airbox mod. The bottom line continues to display the stock power curve. The top line continues to display the power curve with the modded airbox. I apologize for the clunky nature of the blue line, but I was in a hurry and so just transferred the datapoints manually using a ruler as a scale on the chart.
Now all the following is based on my understanding of what BB has said above to be that he had all the mods EXCEPT the airbox mod already on his Graves R3, and now added ONLY the airbox mod.
Is that the case, BB? For example, when you "degreed' the cams, did you simply ensure that they were at the OEM spec settings, or did you advance them or retard them at all?
If so, look carefully at this chart. Notice that the airbox mod is only a BIT higher in power than the prior setup (everything except the airbox mod) UNTIL you get above 9000 to 10,000 rpm. After 10,000, it leaves the prior curve for dead.
Notice also that the prior power peak was at 11,000 rpm, but with the airbox mod peak power is at 12,200 (still within the OEM mechanical rev limit, by the way).
There is no way that the airbox mod alone made THAT much difference, UNLESS the prior tune already had superior breathing ability where the limiting "cork" in the system was the airbox. That is, any efforts to improve power via exhaust or valve timing or anything else was pretty much doomed simply because the exhaust, the heads, the cams, and the valves could ALREADY flow more than the airbox could feed. But evidently, whatever airbox breakthrough Graves has made was sufficient to "pull the cork", and now the rest of the engine and its exhaust can really show what they can do.
This is a rather important discovery, as you could waste a lot of time and a ton of money doing things other than the airbox and not realize that the cork is evidently there.
And that does NOT mean that you should remove or drill holes in your airbox! It is nowhere near that simple. BB, what did Graves DO? I think you previously mentioned velocity stacks in one of your posts. THAT may be a key change.
This could actually be a pretty important "breakthrough", similar to what one of the tuning houses did last year on the Mercedes C63 500+ hp hotrod, when they figured out how to manipulate the variable cam timing system beyond what Mercedes did in the OEM tune.
But BB, we need the BEEF. Please describe precisely what parts and work the mod requires to be done.
Jim G