Camaro wins this one. The Camaro has a10 HP advantage and significantly shorter gearing. The Mustang has bit of torque advantage, but it's also saddled with a 2.73 rear end gear and the non-split port 3.8L which was never rev-happy and was more suited for duty in the Taurus and Windstar than a sports car.
It will be a competitive race though. The Camaro goes 0-60 in about 9 seconds. and through the 1/4 mile in 16.6 seconds An automatic V6 Mustang
of that vintage goes 0-60 in 9.9 seconds and does the 1/4 mile in 17.3 We can knock a few tenths off each of the Mustang's times (provided the driver is competent) since the one we're talking about is a stick shift. Still the Camaro is a little ahead. So it gets the nod in this race.
I'm a Mustang guy, I have an 03 GT w/blower, but I'm not some fanboy that ignores the facts because their not what I want to hear.