ok, i dont know my rear gear, I have 245/60R14 tires on the back, when Im doing what feels like 72ish my speedo reads 102. Where do I change the speedometer gear and what should I change it to??
really need to know the actual rear gear or at least how fast you are going at what rpm, otherwise it will just be an uneducated guess,mark the driveshaft and a rear tire, jack up the car and count how many rev the driveshaft make to one turn of the tire and it will get you close to the rear gear, ex 3 turns of driveshaft to one turn tire, 3.00 gear
By my calculations, with 245/60-14 tires, 4.11 rear and C-4 you would need a 23 tooth driven gear on your speedo cable. The largest I have seen is 21. You might want to check with a Ford dealer to see if they have one.