Changin' from 7.25 to 8.25...speedometer difference?

[Wilnutt]

Is there anything i need from the parts car to make sure my speedometer is right...what will be the difference switching fomr a 7 1/4 to a 8 1/4?

 

[Wilnutt]

bump :thumbup:

 

[dazedduster]

if you need anything it would be the spedodrive gear in the tranny,
Im not sure if switching to rears will affect it id did not change mine
tire size will hange spedo hope this helps some

 

['64 Cuda]

If you're sure that the gear ratio is the same in both rear axles, you don't need to change anything to have your speedometer read as accurately as it did before the rear axle swap. If the ratios are different, take the speedometer drive gear from the transmission. It's a small gear located where the speedometer cable enters the transmission. If you remove the little clamp that holds the drive unit in the transmission you can pull it from the transmission. If the trans is in a car, fluid will come out when the drive is removed. Be ready for it. The gear is usually held on by a small metal spring clip. Just take the whole drive unit if you can. It's always nice to have an extra. If the trans is good, remove the gear & put the rest back on the trans to keep dirt out.

:burnout:

 

[dusterdon]

If the rear end gear ratio is the same nothing needs to be changed. If the new rear has differeng gearing, the speedo pinion will need to be changed, a five minute job.