What RPM is 3/4s of maximum rated Horspower?

[mpeach1976]

Have to get my exhaust tested for decibel rating and I've read that they have you rev your engine to 3/4s of maximum rated horsepower... What rpm would be 3/4s of maximum rated horsepower on 2014 coyote? Thanks for any feedback in advance.

 

[Dino Dino Bambino]

The answer is 4500rpm on a stock '13-'14 GT.