Stimp

I have a 97 svt cobra and just put a 98 motor 4.6 in it does anyone have a diagram for vacuum lines on top of motor? Also my speedometer is reading way fast I have a 19 tooth gear on side of trans would a 17 tooth gear correct this?

imp

Works the other way around. A 17 tooth will read even faster. How much too fast is it reading? Take a reading by milepost to milepost holding speed constant, try 60 mph indicated on the speedometer. Should take 60 seconds per mile. If it took 55 seconds for example, you're off 5/60 or 1/12, or 8.3%.

Going to a 20 tooth gear will slow down the indication by 1/19, or 5.3% not enough. There used to be 21 tooth gears available, a 21 would slow it by 2/19, or 10.5%. That would get it pretty close. Any better would require changing the gear on the tailshaft, which may not be possible. A 2% error would mean when your speedo shows 100, you're actually doing only 96. imp

Stimp

I appreciate the answer I will try to check next time I am out but I am going to say I am about 15 to 20 mph to fast. I think I am doing 55, 60 and speed says 80 but I will try to get an exact number