[Mr70]

Here is what we know on 1970 L-78 Tonawanda Records engine production show:
L-78 Manual CKO engines made-5572
L-78 Auto. CTY engines made-1338
401 of these were Service engines.

3765 X-Body-Nova
2144 A-Body-Chevelle
600 F-body-Camaro

Now for the guesses.
It is Believed that all 600 L-78 Camaros are Manual trans.(Pending Charleys example)

I have a L-78 Chevelle and started a registry years ago.Of the almost 200 buildsheets or related documents I have obtained,they almost always came with a Manual trans.
I have an Auto in my car and only have 4 other Chevelles that came this way too.

I believe the majority of the 1970 L-78 Novas came with Automatic trans.

This is just my opinion from what I have read,seen,and touched.