I wouldn't mess with trying to re-attach the correct ends onto your old original cables.
Keep them on a shelf for reference,but buy brand new complete authentic reproductions from American Auto Wire.
1970 NOVA BATTERY CABLES HERE
http://www.americanautowire.com/shop/nse...res_per_page=96
They are the best & have the correct details like part# & two letter suffix on the cables,both in the right font,as well as the right length for your '70 Nova.
Many reproduction parts houses buy from them & relabel them as their own.
I recommend buying directly from American Auto Wire,and for less $ too,as they know their shit and stand behind it with years of technical experience and many factory examples & blueprints.