Roush 3:73 vs my Speedo

[SKUNK160]

My S281 has 3:55's from Saleen....so if I fit 3:73's in back how much will my Speedo be out? and what would Saleen have done to correct the speedo reading when the 3:55's went in?

Do I need a third party correcting device like the Dallas Mustang’s SpeedCal?

Thanks

 

[Rich Motta]

it needs to be recalibrated...i do not know who does them. your car will be collecting miles a bit faster then it should if you do not get it calibrated.
Rich

 

[ponyguy]

i always wondered, what did saleen do to correct for the 3.55's?

 

[Head Paneer]

I am not sure what Saleen does for pre ’99 cars but on all the late models, the correction is made in their flash program. I plan to move from the current 3.08s up to 3.55s. If I send my computer into Saleen, they will make the gear change for $50.

 

[ponyguy]

anybody know about the pre 99 cars?