[jjaleman97]

My 5.0 is running 10 mph behind. I changed my rear end to an 8.8 inch rear end a while back. How can I get it make to normal and accurate? Thanks in advance.

 

[P4452]

American Muscle and Late Model Restoration are popular late-model Mustang parts sites. They sell the speedometer gears required to correct this problem, typically caused by changes in final drive(rear-end) ratio or tire size.

Here is an example: Ford Mustang Speedometer Gear - 18 Tooth (83-98 T5) C0DD-17271-B||C1DZ-17292-A||53645||53654 - Free Shipping!

There's a chart on that page that will allow you to choose the correct gear for your application.

 

[AMWill]

OP,

Which gears are you using? This will change the proper speedo gear tooth for you application.

Shane

 

[pythontaco]

Why not just drive around with it as is them subtract 10? That's what I did with my ranger. Although it couldn't get up to above the speed limit most of the time.