Roush Performance will soon release its 2015 Roush RS3 Mustang, one of the baddest road going, production Mustangs you can buy. While final horsepower numbers haven’t been officially released, word from inside Roush is that these cars will make at least 630 hp.

In recent years Roush has been known to offer upgrades and enhancements for the RS3 and customers buying their RoushCharger supercharger kits. These typically come in Phase 2, and 3 packages. Each phase is more aggressive than its predecessor and adds more power. Some dealers even install phase upgrades as optional add ons to RS3’s in inventory.

This week, Roush put out a video of one of its RS3 development cars in Phase 1 trim, with a few upgrades bolted to it. Those upgrades included a 75mm supercharger pulley, larger fuel injectors, fuel pump voltage booster, and a calibration/tune enhancement.

The results are impressive, with what amounts to parts that many enthusiasts can bolt on in under two hours, the development car spun the dyno rollers to 747 hp at the rear tires. That’s over 800 horsepower at the crankshaft. This was done with the stock long block, stock exhaust manifolds, and catalytic converters.

This is made possible by the better internal components Ford stuffed into the Coyote for 2015. This engine is essentially the same internally as the previous generation Boss 302. Roush is not the first to push some big numbers on the dyno with a 2015 Mustang, however, its engineering and expertise with all things Ford comes in handy when developing these products.

With this kind of performance out of the Phase 1 with a few minor changes, we can’t wait to see what kind of power the Phase 2 and 3 systems will put out.