KQ rear with 4.56 gears

[69L72RS]

I found a KQ rear that has the COPO 4.56 gears in it.
Were any COPO/Yenko Chevelles ordered with 4.56's like the Camaros or would this has been switched by the dealer?
Thanks
Eric

[Keith Tedford]

If the rearend came from the factory with 4.56-1 gears it would have a different two letter code to identify it. You could even tell if it was posi or non posi by the code. Each one was specific.

[69L72RS]

Not to start an arguement but, I have seen original "BE" rears with 4.56's.
I have also seen "CBW" rears with 4.10's, and 4.56's
that were supposed to be orignal to the cars.
The gears matched the window stickers for the cars and the axle codes matched the POP's.

Has anyone heard of a COPO/Yenko Chevelle ordered with 4.56's

[Chevy454]

I reckon that'd be the *ideal* gear set to have...

[Keith Tedford]

GM shows "KM" for 4.56 and "KO" for 4.88 12 bolt posi rearends. What am I missing? Always willing to learn.

[firstgenaddict]

What does the white COPO out of TN have for a rear end code? It is a factory 4.56 car.

[69L72RS]

Keith,
The "KM" is the standard duty 4.56 (3862515-3862527) rear just like the "KK" is for the standard duty 4.10.
This KQ rear has the correct 3916234 posi unit and the 3917973, HD 4.56 (3916230-3916231)special heat treat, gearset in it.

It is possible that someone ordered the correct COPO 4.56 gears and replaced the 3917971 4.10 gears, but how many people knew that GM had two different 4.56 gear sets back then.

Thanks,
Eric

[Keith Tedford]

Our L78 car has the KK 4.10 rearend while the COPO has the KQ. Until people got into restoring these cars, very few knew the difference or even realized that there were two different rearends. The drag race crowd would be the first to realize that there was a difference. My feeling is that anything but 4.10 gears in a KQ rearend would have been swapped in at some point in the past. Could be wrong though. This is what makes this hobby interesting.

[Stefano]

I thought 4.10 was the lowest gear as factory installed on 69 COPO Cars and if you ordered 4.56s the parts came with the car for dealer installation. It was noted on the Window Sticker and POP with the "right" code, but not the rear axle tube.

[JRSully]

My 69 L78 Nova was ordered with (possibly copo'd from what people have told me) and still has it's original BW coded 4:56 12 bolt, car is an April 69 build