I had heard that somewhere before but I don`t believe it to be true. I looked in my 77 parts book and the 8 1/4 housing does not show it being a different part number for any of the other ratios. If it was a special housing for the 2.45 ratio I would think it would have shown up there. Maybe for some reason later years changed I don`t know. If someone has a 79 parts book then they could look it up for you. I have a used 8 1/4 sure grip if you want to try it in there to see.