Speedometer cluster question

[BigRedMachine]

So my Stang is a 3.9L 2004 40th Anniversary Edition. There was work done on it prior to me purchasing it. Also, I didn't notice how off the speedometer is was I test drove it. Private owner. I am not a mechanic. I took the cluster out and looked up the number on it. It is for a v8. I also has 150 mph on the speedometer. I'm pretty sure my car being a v6 should only go up to 120 mph. Do I need to buy a new cluster specifically for a v6 or can I buy an overlay?
Thanks in advance.

 

[wmburns]

If this were my car I would find out what speed the car is actually going at some easily recognizable O'clock position. Say 12 O'clock. Perhaps use GPS. Or time the time it takes to go between expressway mile markers.

To find out IF an over lay will work look at the speed displayed at 12 O'clock (80 MPH for the 150 MPH GT) but the car's actual speed is 65 MPH (for the 120 MPH V6).

https://lmr.com/item/LRS-17255W99/99-04-Mustang-46-White-Face-Gauge-Kit

how to fix intermittent cluster foil trace repair 1999-2004
https://www.allfordmustangs.com/forums/v6-tech/304608-my-odometer-goes-off.html#2657361

The other way to determine if a new overlay will fix the problem is by comparing the amount that the speedometer is off. The error should be a fixed ratio of 150 divided by 120 which is 1.25.

 

[BigRedMachine]

Thank you for the advice. I will try what you said out in the morning.

If this were my car I would find out what speed the car is actually going at some easily recognizable O'clock position. Say 12 O'clock. Perhaps use GPS. Or time the time it takes to go between expressway mile markers.

To find out IF an over lay will work look at the speed displayed at 12 O'clock (80 MPH for the 150 MPH GT) but the car's actual speed is 65 MPH (for the 120 MPH V6).

https://lmr.com/item/LRS-17255W99/99-04-Mustang-46-White-Face-Gauge-Kit