Going to do a Strange 12 bolt rear upgrade in my 93 Z-28. Will have 3.42 gears in the 12 bolt. Now have 3.23 gears in the 10 bolt. Will have same 275/40/17 tire and wheel combo. Wanted to see if anyone nows what drive and driven gear set will be correct ? Thanks.

Go here:

http://www.transmissioncenter.net/sp...n_______va.htm

Click on the "700R4 Gear Driven Electronic" link.

Or, this is accessible form th eCZ28.com calculations link as well:

http://www.bgsoflex.com/speedo1.html

Thanks again Injuneer !! I will look at those links.