That just goes to show how much the driver really means in a straight line. By all means the viper should have smoked the stang, unless it was heavily modded.
That video is extremely old in internet years.
Obviously the mustang is worked, probably around 400rwhp. Looked to be using sticky tires too, compared to the vipers street rubber.
Back then their wasn't a million different sets of drag radials, only a few sizes.