Should be able to figure out the rpm vs top speed via the gear ratio & tire height and know for sure whether you would run out of RPM before 200 mph...however, speaking from experience, getting a vehicle above 175 gets exponentially tougher each mph added...it is like hitting a wall. A car that plateaus at 175 mph and does not have enough hp to overcome wind resistance would need 10 to 15 more HP to go 5 mph faster and so on - I would expect an SRT-6 that was geared to turn 6,400 RPM at 200 mph, AND made over 425 hp to the ground would be capable if prepared correctly - and didn't break traction at the top end...sounds like it would be fun to find out!!