I don't think 140 would be difficult at all for this car. For a driver to keep his foot in it long enough, now that would be difficult, but not for the car.golf4283 said:
With a 26.35" tall tire, 3.73 gears, and assuming that 6th gear in a T-56 is .6, that would equate to roughly 4000 RPM @ 140 MPH. Granted, the car has the aero dynamics of a brick, but that's not enough to keep it from 140. 205 MPH on the other hand is a pipe dream. The engine would only be turning about 5850 RPM, but not even the ROUSH 402 R engine has enough horse power to push the car that fast.
When I was young and very dumb, I took my '68 coupe to 120 once, and there was still some more to go. I only have a 4 spd and a mildly warmed over 351W. With a 6spd, the ROUSH 402 R engine and cajones the size of Texas, I know my car would do 140 easily.