Battery Recommendations..
The BCI (Battery Council International) Group size top post battery for a 1972 Demon is Group 24, without suffix lettering. Group 24H and 24T are ~1/2" and ~3/4" taller respectively. Group 24F and Group 24R are the same in size, but have the battery post terminals reversed for Ford and other applications. A Group 34 battery can be substituted if using a 1" spacer or shorter J-bolts. Group 34 is the same length and width but is 1" shorter. Group 34R batteries have reversed terminals. For more information about BCI group sizing, terminals, etc, see BCI Assembly Numbers, Cell Layouts, Holddowns and Polarity.
Various battery brands can vary widely in ratings, performance, and durability, even within the same brand. Most automotive batteries are actually made by a few manufacturers and distributed under various brands. I currently use Deka for Absorbent Glass Mat (AGM) batteries, although these are not available in Group 24. Deka AGM is available in Group 34. For flooded lead acid batteries, I use Continental (the tire manufacturer). The Continental batteries are available at my local parts store, and they are plain black, so I can "dress them up" as Mopar batteries using a Weskar kit:
So far the Continental have been performing well in both Group 24 and Group 27 sizes. Group 27 is a longer, higher capacity version of the Group 24.
The BCI (Battery Council International) Group size top post battery for a 1972 Demon is Group 24, without suffix lettering. Group 24H and 24T are ~1/2" and ~3/4" taller respectively. Group 24F and Group 24R are the same in size, but have the battery post terminals reversed for Ford and other applications. A Group 34 battery can be substituted if using a 1" spacer or shorter J-bolts. Group 34 is the same length and width but is 1" shorter. Group 34R batteries have reversed terminals. For more information about BCI group sizing, terminals, etc, see BCI Assembly Numbers, Cell Layouts, Holddowns and Polarity.
Various battery brands can vary widely in ratings, performance, and durability, even within the same brand. Most automotive batteries are actually made by a few manufacturers and distributed under various brands. I currently use Deka for Absorbent Glass Mat (AGM) batteries, although these are not available in Group 24. Deka AGM is available in Group 34. For flooded lead acid batteries, I use Continental (the tire manufacturer). The Continental batteries are available at my local parts store, and they are plain black, so I can "dress them up" as Mopar batteries using a Weskar kit:
So far the Continental have been performing well in both Group 24 and Group 27 sizes. Group 27 is a longer, higher capacity version of the Group 24.