Rear gear ratio

[Larry S.]

I am buying a 1966 big block (427-450) coupe that is numbers matching. Can anyone tell me how I may tell what rear-end ratio is in my Coupe?
I mean is there any numbers stamped or tagged on tne housing that could tell the original ratio?
Also, does there exist info on the history of a corvette going back to its purchase from GM (using the VIN#)?

[Terry D.]

Re: Rear gear ratio

Larry

Differential code is stamped on the bottom of the differential carrier housing just forward of the rear end cover. It is a two letter code, most starting with A. You could always do it the old fashion way and jack up the car and spin the tire one time and count the drive shaft revolutions.

You might want to buy some reference books BEFORE you make that purchase so you can be sure it is "numbers matching"

No info history that I know of.
Terry

[Terry D.]

Re: Rear gear ratio

Larry

If you get the code letters e-mail me and I will look them up for ya
Terry

[Verle R.]

Re: Rear gear ratio

Larry,

If you are not knowledgeable about these cars I suggest you get someone with that knowledge to inspect the car.

NCRS members live all across the country and are willing to look at cars for others. You should be willing to pay some fee for their effort. It takes a lot of time to do a thorough job.

We have seen numerous examples of someone buying a "numbers matching" car that didn't get what was advertised. Part of the problem is the definition of, "numbers matching". It is not a simple concept.

There is no known database with history of Corvettes older than 1984 and the VIN of a 66 does not contain much information.

Good luck,

Verle

[Larry S.]

Re: Rear gear ratio

Thanks, Actually I just found a listing on the net under www.corvette.net/tech

Thanks everyone.

[Bob S.]

Re: Rear gear ratio

Larry - When I bought my car the previous owner wasn't sure the actual ratio matched the two letter code. (He thought it had been changed.)

After putting the car on jack stands, I rotated the driveshaft and counted the turns. I made enough rotations so the rear tire rotated 10 times. Since it took 37 driveshaft revolutions to make the tire rotate 10 full turns, my car has a 3.70 : 1 ratio. (You could try rotating the driveshaft only enough to make the tire turn once, but it would be difficult to tell the difference between 3.55 and 3.70 driveshaft revolutions.)

Good luck with the purchase!

Bob