74 speedometer gear question
Racer
Joined: Mar 2009
Posts: 394
Likes: 1
From: Everywhere US
this might help ..... without knowing what drive gear is in the tranny, its difficult to calculate .....
but check this ..... http://www.bgsoflex.com/speedo1.html
but check this ..... http://www.bgsoflex.com/speedo1.html
Race Director
Joined: Oct 2000
Posts: 12,710
Likes: 3,163
From: Shamong, NJ
this might help ..... without knowing what drive gear is in the tranny, its difficult to calculate .....
but check this ..... http://www.bgsoflex.com/speedo1.html
but check this ..... http://www.bgsoflex.com/speedo1.html
You need to know the final drive ratio and the tire diameter.The 74 Assembly Manual has a chart in it (UPC 12J - Sheet 6), that lists all of the engine/trans/rear combinations, and the proper speedometer gear as installed at the factory.
As an example, from the chart a 74 Corvette with automatic, the 3:08.1 rear and standard GR70R15 tires (P225/70R15 in today's sizes); used a pink 35 tooth driven gear.
