Cam Upgrade for my 408. Need some advice.

With how quickly the power is dropping off at the top of the dyno sheet, I suspect some valvetrain stability issues.

I feel like the 20-741-9 cam should be 500hp capable in that basic combo, and is probably as big as I’d go with the EFI and current converter.
With the proper springs, it would def peak at a higher rpm than the current cam and have usable power upwards of 64-6500rpm.