I can only guess but I believe my car would put down some wear between 420 to 430 WHP on a different dyno. These Mustang Dynos are known to be stiff or read a little lower then other dynos.
I Don't think I will be trying to force any more power out of my stock 7 bolt frown
She has had a good run 30 + psi since 2011 and still ticking, lifter ticking that is frown
The last compression test I preformed on her was 150/150/150/150 psi.

Tomorrow morning I will be drag racing all day on the abandoned run way behind 12 Wing Shearwater For the MP's Race the Base charity event.
I wonder how much more punishment my engine can take before she gives out on me.

But back on the main topic Brian I defiantly recommend you go with the 68HTA with an external waste gate and if you have access to 94 octane pump gas+meth you should be able to obtain the power levels you seek if your car is mechanically sound with an efficient setup of course.

Just Because you are not paranoid dose NOT mean they are not out to get YOU !