Speedo gear

[1966satellite]

My car has 255/60/15's on it and a 3.55 posi rear end. I put a 34 tooth speedometer gear in the 727 but it appears that the speedometer reads 8 to 10 mph fast at 50 mph. Anyone have any idea what's wrong? Everything I've seen says that 34 is the correct gear.

 

[Greg Ducato]

If that is a 27 inch tire and those are the gears then that is the correct number of teeth for the driven gear. You may have some speedometer error I would think

 

[sleepar]

A weak spring in the spedo... does the needle bounce at all.... Or you don't have the gears you think you have...

 

[1966satellite]

I checked the gear an it is 34 tooth (green). The speedometer does bounce so maybe if I lube the cable it will get better.
Thanks for your help.

 

[themechanic]

Read post #12. http://www.forbbodiesonly.com/moparforum/showthread.php?7246-Speedometer-jumping

Also, IIRC on another forum (Mopar Action Tech Article Archive) Rick Ehrenberg recommends a thick grease like wheel bearing grease leaving the last 6 inches on the speedo end dry as not to get into the speedo itself and gum things up.