I'd say it's all about traction. From a dig, my fox body would have to play catch up with my un-tuned, stock MKS. I'm sure that, with some killer help, my MKS will then be able to hold it off for quite awhile.
That being said, horsepower to weight ratio becomes an issue at higher speeds. My fox body dyno'd at 532 whp and weighs 3150 lbs. There's no way for ANY heavy modern car to hang with it at speed unless it puts down a LOT more HP.
The crazy thing is that my fox body isn't even fast by today's standards.
I've never owned a stock Mustang for more than a few days though. The aftermarket and potential is just insane!
