Hello , I have a 1970 Chevelle Malibu and wanted to know if sombody can tell me what the gear ratio is ? there are 10 bolts on the diff, cover .

what size motor from the factory? does it have A/C? is it a TH350,TH400 or 2 speed?
Answering these questions will help...or you can always pull the cover and count the teeth or do the driveshaft/tire revolution check.

The motor is a 350 & its a 4 speed with A.C.

Look on the axle tube for the axle code. It will tell you exactly what you have. You may have to take a wire bruch to it to find the stamping, But its there.
http://www.chevellestuff.com/1969/rear_axle.htm

This is what your looking for.
http://www.chevellestuff.com/1970/images/rearend_70_ccf_0325b1.jpg

Thanks for all the Help .