Same here, what were the stock gears in your car. It will never be dead on anymore because the highest speedo gear they made was for 3.55. Not sure on the top speed, its going to depend on the gear ratio, tire size, how much power your making and the aerodynamics of our cars so couldnt tell you. Chances are it being off you were probably going like 130-140. I have had my speedo pointing straight down and it still pulling but then again I have 3.90s and a 3.08 speedo gear so Im not sure how fast I was actually going.
my car is bone stock. automatic with 3:27 gears. at 115 with the pedal to the floor it shits into overdrive and i had my foot through the floor board pretty much for what seemed like forever and i finally hit 125, it just didn't want to climb hardly at all. don't know if there's something wrong with my car or not