This is the only one that I know of running 8s...I was just curious about the Supras, I wasn't aware of any. No, the 427TT did not have the boost turned up. This is the car Lingenfelter is using to establish the numbers it puts out for PR. Its still under warranty.
A 427TT running stock boost is putting out over 850hp from what I've heard. A N/A 427 is probably making between 500 and 600 hp...after all, its using the same block that the C5-R uses, but detuned for street use. The C5-R makes 620hp in race form, but it is running restrictors that the street 427 isn't.