Speedo doesn't matter. All -- GT, Boss, GT500 -- are governed. My
guess is the GT could tickle 170, the Boss around 175 and the GT500 in
the 180s if they were let loose.
the computer leans out the engine about 110 or so, rev limited.
So you have to have a chip with it set higher, to go fast as the speedo
they used to be set around 140 for 1990 5.0 speed density.
but they dropped them back to about 110 for safety, no reason to have granny
flying down the highway at 140mph
But there are very few streches of good road to drive at 120 to 140 mph in
the USA, too bumpy. not designed for it
I did 135 mph for about a mile, once, and other cars are not looking for you
at all, you are going twice as fast as they are.
Also you have to have the good tires Z rated or higher speed.
dont want the highway rated (90mph) tires flying apart whilst you doing
I won't ever know how fast it can go. I tend to be more cautious as I
get older (I kinda resemble your granny remark:) I get up around 100 and
start to get a little nervous. I know my reflexes aren't what they used