Blue what fuel pressure where you running??
On the dyno it was holding right at 90 psi dual fed so all (6) barrels should have seen close to that much pressure.
I have another run that was started at 3400 rpm and ran up to 4500 rpm. It made:
630 @ 3400
626 @ 3500
630 @ 3600
622 @ 3700
612 @ 3800
598 @ 3900
580 @ 4000
560 @ 4100
516 @ 4200
475 @ 4300
429 @ 4400
400 @ 4487
The afc is setup to not allow full rack travel till 55-60 psi boost. On a pull that starts at less than 2000 rpm, it achieves full rack travel fairly early in the run and starts losing fueling, likely cavitation above the plungers around 2750-2800 rpm.
On this run, since it started much later, it carried the fueling out to a higher rpm. I don't have a data logging setup so it's difficult to know for sure, but it almost seems like the afc was still limiting rack travel at 3400 rpm because there is a small dip in power that starts at 3440 rpm and peaks again at 3627 rpm meaning that power increased so it's probably that the afc was still advancing and therefore the rack was still advancing.
What this leads me to believe is that if the rack travel isn't maximized, the 160-175 pump setups can achieve higher than 2800 rpm fueling. Without getting too deep in plunger design, when the barrels are racked, the afc is modded for max travel along with the 2095 rack plug, the barrels are able to rotate to the point that the fueling is no longer working off of the lower helix ramp/spill port, it's simply fueling till the plunger stops moving upward which provides an even more narrow window of plunger re-fill time.
***Without extensive testing this is just a theory***....it might be possible to maintain higher average horsepower in the 3000-4000 rpm range if rack travel is limited to stop the plunger rotation at the end of the helix rather than rotate beyond. This gives a shorter injection duration but does provide more fill time. On my setup, it looks like it might be possible to carry 600 HP up past 4000 rpm if a plate is used as a fueling stop.