Rear Differential Removed for Rebuild

The code for the rear differential indicates that the ratio for this car is 3.08, pretty common actually for the Corvettes made around '75.  This ratio is referred to as an "economy" ratio, so it's meant for higher speeds but is bad for initial acceleration.  So with a 3 speed automatic transmission, this was an attempt at getting better gas mileage on the highway.

With the transmission out of the car, my wife and I have decided to upgrade to an automatic transmission with overdrive (a level 2 200-4R from Bowtie Overdrive, I'll talk about that later after I get the order in).  Adding the overdrive gear eliminates the need for the "economy" differential ratio.  Researching ratios, and talking with my mechanic, I've decided that a ratio 3.55 is good for this car.  It will get much better off-the-line acceleration, and still have acceptable highway response.  I had thought about going to 3.70, but after discussing with the mechanic, that was completely taken out of the equation because highway driving is supposedly not good with this ratio or higher.

A mechanic at the shop that's doing my engine does differential rebuilds.  He's agreed to rebuild mine with the different ratio so I spent the night removing it from the car.  By the way, it's heavier than you think it's going to be...