rear end gear swap

does any one know what gears the 1985 monte ss came with because i've done research and cant find jack but it would be nice if someone answered this time

okay you guys suck i know its a 7.5 rear end now can any one tell me what gear is in it or do i have to tear the ****er apart ?

They usually come with a 7.5" but in all honesty you will have to rip it apart to make sure.  You can see if you can find the axle code.  If you can go to http://www.nastyZ28.com

the gears are usually 3:55 for the 1985 - 88 with overdrive models and 3:73 was an option for the 3 spd 1983 1/2 to 1984. some were one leggers too as posi was also an option.

So in short, you will have to tear it apart.  On the passenger side of the drive shaft tube, if you can find the code for the axle, it will tell you the gear ratio, the size, if it's open or LSD.

Let's see, he posted his problem in April of 2006 and we responded in February of 2007.... I wonder if he got it figured out yet?
 
By the way, you can determine gear ratio's pretty closely by counting the # of driveshaft revolutions needed to make the rear wheels turn 1 revolution.....  No disassembly required....

All Monte SS's that I'm aware of came with a 7.5 or a 7.625 rear with 3.73 gears, 26 spline axles. Buick T-Types and GN came with the 8.5 rears with 28 spline axles.