1970 Diff Code for L78?
 

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

Re: 1970 Diff Code for L78?
 

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

Re: 1970 Diff Code for L78?
 

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.

Re: 1970 Diff Code for L78?
 

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. https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

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

Re: 1970 Diff Code for L78?
 

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.?

Re: 1970 Diff Code for L78?
 

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

Re: 1970 Diff Code for L78?
 

Deuces have 4.10's, coded CBW.

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

Re: 1970 Diff Code for L78?
 

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

Re: 1970 Diff Code for L78?
 

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.