Re: Battery Size?
You're making it too hard :-) Call any large parts house (Checker, Autozone) and ask them what listing they show. It's expressed as a GROUP #, ie Group 43. There's no rhyme or reason to the group #s, a 43 might be smaller than a 22 or vice-versa. I'm sure Interstate shows two sizes because Ford did provide a batt w a higher capacity in things like towing or snow-plow packages. Just get the best you can buy, either model should fit physically (I'm sure Ford used the same batt tray either way). I can tell you it'll be *roughly* 11" long by 7.5" wide by 6.?" high. I only know this because I was recently trying to squeeze my old Bronco batt into my daily driver.
You can put in whatever you want, just take measurements of your battery tray and go from there if you choose, you can buy universal j-hooks and hold-downs to retain any size battery. Now that I think about it, the Bronco might take a Group 65?