73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Jay2D2 on January 31, 2009, 07:48:35 am

Title: Final Drive Ratio
Post by: Jay2D2 on January 31, 2009, 07:48:35 am

Hey guys just wonderign if there was a common rear gear ratio on a 82 k25 with a 400 trans and a 14 bolt 10.5 or did gm have options in that one too

also in relation to the front diff and rear diff do the ratios have to be the same?

Title: Re: Final Drive Ratio
Post by: zieg85 on January 31, 2009, 07:56:45 am

GM offered many ratios.  Check to see if the sticker is still in the glove box which should tell you.  The rear-front diffs ratio can vary but not much.  An example would be 4.11 rear 4.10 front, at least that was the case in my 72 K20.

Title: Re: Final Drive Ratio
Post by: Captkaos on January 31, 2009, 11:20:19 am

There is only one way to tell and know for sure on a vehicle that old, pull the inspectin cover.
Most of the ones I have seen came with 3.73 gearing, but that doesn't mean yours is that way.
The front and rear can only vary 1% for a vehicle that sees highway use.