[Mr70]

If the letter E-May & F-June, are inbetween the ribs then that's the month code.
The letter I was not used to date the Tanks either that I have seen,so M was December.
If there was a suffix tag attached,it would have the actual radiators part # on it.
Kinda difficult to find anymore specific application info w/o the suffix tag attached.
Your 1970 L-78 Nova Radiator would have had a ZE suffix tag,part #3017838.
That CH tank would've been found on the TH400 1969 Big Block Camaro too.