Yes,but I've only found 3 out of 200 so far,including
MINE. 
If anyone has proof of another 1970 L-78/TH400 Chevelle,please let me know.
I too believe that at least one had to be built with the Camaro,but Tonawanda records & salemans materials would indicate differently.
The 1970 L-78 Novas seem to be the model most favored by the TH400.
In fun,we subtly gang up on Charley as he has seen the paper for this example,but can't get pics of its paperwork.
Quite honestly,if Charley says it does exist,that's good enough for me.