Packard Forum Index » V-8 (1955-56)

Hi All,

Well the engine is back in the Packard (again) my engine rebuilder believes that the wrong diff gears are installed in the 55 Caribbean. When I purchased the vehicle the car had a manual gearbox installed. I have converted it back to auto. On the dyno I'm doing 3000rpm at 60 miles/hr. Its also using a bit of furl, but as i'm still running the engine in this is to be expected. I will check tomorrow what the current diff ratio is, but at the moment I am running a 374cui v8, twin 4bbls, and a torqueflite 727, considering these characteristics what would be a recommended diff ratio to use. I noticed the ratios ranged from 2.87 to 4.09

Any help would be greatly appreciated

Mathew

packard34, is your speedometer reading accurately? The speedo drive in the trans may be for a different axle ratio.

(o{}o)

The majority of automatics in 55-56 were using 3:54 rear ends.

At the moment the speedo cable isn't connected as their is a problem with the speedo drive in the gearbox but am using a gps speedometer system. Thanks Randy for the diff ratio. I haven't check my ratio yet but hope to do so over the weekend

many thanks for your help

Mathew

If the manual you removed came from the factory then typically ratios on 55 standard trans was 3.9