*Blk_96_Stang_GT*

The guy i bought the car said that he had 3:73's put in it, but at 60mph im running 1900rpm...but the speedo is 10mph so somthin was done.

red2k1gt

the speedo is 10 mph off?

*Blk_96_Stang_GT*

when the speedo says 50 im going 40....so the gears were changed, but everyone else with 3:73's says they are at 2200rpms at 60mph

red2k1gt

Still have the stock height tires?

*Blk_96_Stang_GT*

yep

gt96stang

Yes, I have 3.73's and my speedo is 10 mph off.

jdaniel

You need the speedo gear for 3.73's and that will fix your problems... assuming you really have 3.73's.

PipsBlackStang

I posted about this awhile back and I found my answer on another site. Jack up your car. Have some one rotate a rear wheel 1 rotation and you count how many times the driveshaft spins. Chalk is really helpful when it comes to counting it spin. I still havent gotten my 3.73 speedo gear thingie so Im not driving it because ghost miles are gay. I wonder how many real miles are on my car?????

*Blk_96_Stang_GT*

would changing the gears, make what ur RPM reads wrong?

red2k1gt

definately...changing to a higher gear causes higher rpms which will make your car think your going more miles than you actually are.