1970 Diff Code for L78?

[Seattle Sam]

I'm looking for the correct differential code for a 1970 Camaro with a 4.10 gear. Colvin's book gives both COO and CRE codes for 70 Camaro 4.10, and he doesn't differentiate between posi and open. Are either or both of these codes correct for a Norwood-built L78 car? Were all 4.10 gearsets sold with posi?

Any help is appreciated as always..
-Sam

[Belair62]

Mine is a COO 4:10...I think all 4 :10's were posi.

[Mr70]

Both those 4:10's were posi.
I believe the reason for the two 1970 Camaro Posi codes,CRE & COO,was they anticipated the 1970 Camaro to recieve the LS6 engine from the line.
One 4:10 was to be destined for the L78,& the other the LS6.

This is true with the 1970 Chevelles.
The LS6 gets a CRW(Heavy Duty) 4:10 posi,& the L78 gets a CKK 4:10 posi if ordered.

Obviously the 70 LS6 Camaro never fruitioned,so they modified the two to be compatible with the L78 engine or LT-1 Camaro-Nova possibly?
Just a theory.

[Seattle Sam]

Thanks Rick. It looks like all the CR- codes have an exact match with a CO- code. Also noticed that there are four codes for a 2.56 open diff, COA, COB, COM, as well as CRF.

The Nova rears were one inch narrower, and the spring perches were not the same distance apart. The highest ratio listed by Colvin for a 1970 Nova is 3.55 (CBT). What's in all those Deuces?

-Sam

[JRSully]

The lowest gear you could get from the factory for a 70 Nova was 3:55, The Deuces were copo'd with special 4:10's, possibly 4:56's.?

[MagicRatt]

My Norwood car is coded "COO" and is a true posi with a 4.10. The ring gear is date coded 2/70.
Rich

[YENKO DEUCE REGISTRY]

Deuces have 4.10's, coded CBW.

When Alan wrote the books, the COPO Nova specific code was not yet known.

[hvychev]

Marlin is what I heard before that Yenko Deuce Novas had the highest "factory" gear ratios for all Novas?

[YENKO DEUCE REGISTRY]

That's probable for '70, but not sure on earlier models. It is quite possible that some of the hi-po Novas from '66-'69 came with 4.56's.