Please try to read the entire post first.
The dyno pulls were made in 4th gear due to the car hitting the speed limiter in 5th gear.
87 vs 93 Octane Dyno Graph ----->>> - The Mustang Source - Ford Mustang Forum
both still above 350whp...
Can you please provide that proof? I think you have it backwards.
Regardless, it is the delta (before vs after) that is the meaningful part of this sort of test, not how high (or low) the HP was compared to some other car on some other dyno.
backwards
It's been mentioned before this is my quickest "proof" a photo of this months 5.0 mag