I have the set up you describe. 235 with a Saginaw 4 speed 1:1 ratio and the 2.73 rear. If you live in flat land country such as Texas you should be fine. You should try to find the Saginaw with the 3:50 first gear which is easiely identified by the 2 grove input shaft marking you will be ok. Another gears to consider for Texas are the 3:08 and 3:32. I would not go any deeper than that. With a properly tuned 235 and the 2.73 rear gear and the 4 speed you'll easiely get 18 mpg.

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