Battery sizes are classified by groups. The MJ factory battery size is a group 58 series, and all group 58 batteries regardless of the manufacturer are supposed to be the same L x W x H. The slightly taller group 34 series batteries will also fit our trucks, and they have a higher CCA rating than the group 58's simply because of their larger size and plate area.
The factory hold-down works with either of these group series. Doing a quick search, it looks like they don't make a Diehard group 58 series battery.