[rotorwrench]

Fords used both the BCI group 1 and group 2 batteries in the 6-volt era. A lot depends on the size of the battery box. While there were variations in size of these batteries back in the 6-volt era, this is not the case in the modern era. NAPA and O'Reilly's still carry one or more of these group types or they can likely order them.

The group 1 size is: 9" L X 8.75" H X 6.875" W and was used in the older cars and a lot of tractors.

The group 2 size is: 10.375" L X 8.75" H X 6.875" W and was used in the later cars that needed a bit higher cranking amps for better reliability.

It's hard to tell now days who sells the lowest price battery of those that still carry them. The lower priced ones for cheap skates like me would have the higher probability of being a freshly manufactured battery. Manufacture date is critical for a wet cell lead acid battery. The newer it is the longer it will last for the most part unless the manufacturer doesn't have any quality control in their process.