I'm new here but had the same question concerning the battery. I asked the 80-82 NCRS Team Leader and his response to me was:
"Donald,
Look for a Delco/Delphi group 75 side terminal only battery. I own a 82 Collector and I’ve got a Delco 75A72 battery. (Group 75 72 month warranty) It cost $69.99 (+core) at a local discount parts place (Murry’s Discount Auto Parts). I could have purchased a 75A84 for $10.00 more but deceided I’d try to stay as close as I could to the original batteries CCA rating of 485. If you go to a GM (Chevrolet) dealer they’ll sell you a group 70 which is a smaller in size battery but closer to the original CCA’s. As you can see the grouping numbers of 78/75/70 have to do with the physical size of the battery.
Any non GM battery receives zero points in flight judging."
If you need anyother info from him his e-mail address is
ncrs78_82@hotmail.com and his name is Brian Pierce.
I am registered to do my NCRS Regional the first weekend of November, and can't wait.