I never been in a slant that didnt have a 2.76 rear. That's saying I've been in only a few slants but they were all 2.76, except Raj's that had a ridiculous 'Doba 2.40ish rear gear. New oil, filters, coolant flush, roll of duct tape and drive it!
Almost all early-A 225's came with 2.94's & 13" tires..including both of My '64 GT's. The 'vert is a 3-on-the-tree, the Cpe is a PB auto.
My '69 Dart Custom 225 auto; 2.76's
My '72 Swinger 225 auto w/air; 2.76's
The '76 4-door w/discs & LBP 7.25; 2.76's
Early A's had smaller cams, the bump in cam size may have coincided with the drop in ratio, even tho' the cars were getting heavier as well.