1969 Chevelle 12 Bolt
 

I have a factory CI coded 1969 Chevelle 3:73 12 bolt posi out of an L78 with a casting number of 3959038. My question is, would a 4:88 gear fit on this carrier or would I need to make changes?

If you are talking about the center unit, they sell thicker gears that fit the 3-series unit. The housing will fit any gear ratio.

The special thick 4.88 use to be kind of common, but this is the only one that I could find. https://www.ebay.com/itm/Richmond-4-...frcectupt=true

Thanks for the info. This will help.