Samantha,
Yes, the 390 ratio may be the same but I really want the overdrive trans. My experience with several AD pick ups has convinced me the GM engineers really knew what they were doing when they matched the 390 rear end with the 1955 (and later)overdrive transmission. The combination gives you low rpm at highway speed and low enough gearing to pull from a dead stop. I have had 373's in a 1965 rear end combined with an overdrive trans and the 373's are just a little to high to pull a trailer up a hill or for a snappy start from a stop light (with a stock 235). We bought a 1950 Crown 14' travel trailer so I am getting picky about having both the low end pulling power and the low rpm's on these California freeways. In addition to all of that, the Chevy 3 speed OD trany has a lot of fun driving features, including free wheeling and shifting without the clutch at low speeds and gas peddle kick down shifting at higher speeds. I highly recommend it to any fellow bolters who drive much on highways.
Thanks. Rod
