The 2.73 gears will not work behind any OD transmission. A 235 simply can not push it. I would think that it would be tough for a 235 6 banger to pull a .63 OD at all. You would almost have to run 4.57 gears behind it to give you a final drive ratio of 2.87:1. Realistically for economy and performance the final drive should be close to 3:1, with about 2.73:1 being the highest final drive ratio. Others will disagree with me.
Final drive ratio equals the (rear end ratio) X (transmission ratio in top gear)
In my opinion, the perfect ratio for a 235 would be 3.73 gears with a .72 overdrive and tires with a 26-28 inch diameter.
Hope that helps.
John
