are you sure you can hit 180mph in the srt6? not saying it doesn't have the Horsepower to do it, but wouldn't you hit the rev limiter in 5th gear long before you make 180mph?

I will have to look at the gear ratios on the auto and final drive ratio, assuming you bumped your rev limiter to 7000rpm. I'll let you know what top speed is really limited too. later!