that pulley probably is only 2x the diameter of the stock pulley and will only get you to about 10mph. To get 5x stock speed, you need a 5x bigger pulley. The big problem is a 14" wont fit. You will have to find out how big will fit in the front, then change the TX to a smaller size to get the top speed you are looking for. Dont forget that the clutch, idler and belt will probably need to be changed too, so this wont be a $15 upgrade to go that fast... $100 is a more realistic budget for this.