Will changing the gear ratio affect the readout of the speedometer?

[mamastang]

I was wondering if changing the gear ration to a 3.73 will affect the read out on a 97 Mustang GT? It is a 4.6 with a 5 speed.
Thanks
D.P.

 

[sgarlic]

Yep. You'll need one of these to fix it... http://www.brothersperformance.com/catalog/product_info.php/products_id/1327

And before anyone chimes in about "use the Dallas Mustang one instead," they are the same friggen thing, the Brothers is cheaper, and the DM are the brand that had the bad batch of speedcals, not Brothers.

 

[stangGT97]

yes it will. you can correct it by installing a Speedcal (available from dallas mustang), that will run you about $99 depending on if you buy it new or second hand.

 

[CobraRed_96_GT]

im putting mine on tmw. Just had my 3.73's put in thursday, on the freeway at about 60-65 it says 85 or so i think. I have the borthers speedcal, got it for $50 shipped used.

 

[TweekedGT]

You don't even need a speed cal. All you need is a little toothed plastic gear for the tranny. Cost me $25.

Look at the bottom of the page of the link.
http://www.haneymotorsport.com/Ford 8.8 gears_and_accessories.htm

 

[Seraphitia102]

my speedo was off about 15mph when my gears went in