dude, better doesn't mean faster
thinking it would be faster won't make it faster, but we would find out really soon....
i don't see why it should be faster, close HP numbers, but the mach is still making hp at 6100rpms, better Torque Curve on the 05 GT???, yes, but the lt1 is even higher and flatter, and still is a 14's car.for the people that swear torque is everything, look at the powerband of a stock lt1 and you would see what i'm tlking about..., close weight,same gears,same trannie,etc,etc.
unless that 3V engine is putting down more hp than a mach 1, (we don't know yet), it won't be faster than the "old" mach 1.
Note: since i don't know how fast the 05 GT really is, i could be speculating like you....would see who is the fastest N/A mustang ever pretty soon...