C3 conversion for CSX style chassis

[moore_rb]

Originally Posted by Tjd

Believe the C2 and C3 cast-iron cases use the same mounting the C3 aluminum cases have the front pinion mount cast. trying to find a used alouminum case now to check that.

Yes, most C2 and early C3 Corvette diff cases (up to 78) are externally very similar- everything bolts up in the same places...

I also agree with Tom Wells that the later-C3 aluminum cases (the "O" cases, as in "Oh my God, what a piece of crap") should be avoided in high HP applications. From the factory, these cases were only used behind smog-era small blocks that barely made 150HP at the rear wheels.

This is very cool work, and would be a great alternative for guys who want a cheaper, stronger, and more readily available alternative to the Jag-style diff...

Corvette Diffs are all over the place, and one other nice thing about them is that they were factory stamped with a code that tells you just about everything that is going on inside the case (gear ratio, and whether it has open spider gears, or a posi/limited slip carrier) You can even tell from the stamped code whether the posi units were originally an Eaton posi (used most often behind small block cars), or the the Warren (Auburn) posi carrier that was most commonly used under big-block Vettes. (there are numerous exceptions to this rule, and there are many 66-67 big-block vettes out there with Eaton diffs, but the vast majority of big block Corvettes were sold between 68 and 71, and 80% of those cars had Warren gear cases and posis)

for penny-pinchers who might want to save a few extra bucks by sourcing their own diff from a junkyard and having it rebuilt, Wilcox Corvette has done a ton of the footwork putting together the list of factory stamp codes that will help you determine which corvette gear cases might be best for your project:


63-67 Corvette gear cases:
1963-1967 Corvette Rear Axle Codes and Ratios | Willcox Corvette, Inc.

68-70:
1968-1970 Corvette Rear Axle Codes and Ratios | Willcox Corvette, Inc.

71=82: (remember: Stay away from the "O"s if you plan to add big HP):
1971-1982 Corvette Rear Axle Codes and Ratios | Willcox Corvette, Inc.


Hope this helps...

[my427cobra]

I'm learning so much here as I shift through all the responses:

Cast iron cases: 1963 to 1975

Aluminum cases: 1976 to 1982

Auburn Posi: 1963 through 1967

Warren Posi : coded with a "W" suffix in 1968 through 1970 otherwise Auburn

So I'm looking at Tom's pictures of his adapter:

He appears to be using a Dana 44 rear cover (with filler plug and breather), bolted to the rear of the adapter.

The adapter appears to be fastened to the diff housing with countersunk fasteners in the Corvette diff bolt pattern.

So you use a Corvette diff gasket on the front side and a Dana 44 gasket on the back side

Am I right so far?

Cheers
Greg