No announcement yet.

3:54 gear ratio

  • Filter
  • Time
  • Show
Clear All
new posts

  • 3:54 gear ratio

    I just got in a 1951 studebaker automatic car today. I checked the rear end and it has 3:54 gears. I have an application where i want to put in a 1952 Champion. Of course, it has a champion motor in it. Currently, I have a 3 speed od. Now what is the pro and cons on the rear end and will it give me any ++++s by putting it on the car. Currently, the 1952 car has the basic od trans for 3 speed od. rear axle.

  • #2
    I'm not sure about the 51 or 52, but in 57 the automatic Champion has a 3.54 as well, and the normal R/A ratio for overdrive with a Champion 6 is 4.27 (early years might be a 4.56?), and with with standard shift its a 4.10. All this makes perfect sense back then because higher rear end with an overdrive means you can have better acceleration, with just a bit better top end. The downside to 50s thinking is that if the overdrive stops working for any reason, then the car is not drivable on the highway. Today's thinking would have it with a lower ratio R/A for faster/quieter highway cruising with better mileage and also a better ratio for on-ramp acceleration, and no difference between conventional and overdrive.

    However, you should know that in 1959, with the return to a flathead 170 @ 90 hp, from the 55-58 185 with 101 hp, the factory did a bunch of tests of both the 6 and V8 with standard and definitely NON-standard ratios to test out gas mileage at steady speeds. They tried the 6 with 3.54 auto, 3.54-3.73-4.10-4.27 on both straight shift and overdrive. The V8 with 3.31-3.54 auto, and 3.31-3.54-3.73 both conventional and overdrive. The mileage figures are quite interesting. I can't post a picture to the forum, but I'll send you a PM with this as an attachment. You might want to post this if you can. I think that if the factory did it, it might be worth a try to use the 3.54 with an overdrive Champion. The only change is that you might want to run it in 'lockout' more of the time, unless you are going to be doing highway driving, and use the pinion gear from the automatic. If you have an over-bored engine, it is going to be in the hp range of a standard 1959 flathead engine anyway.
    Last edited by Jim B PEI; 05-10-2011, 03:32 PM. Reason: or 52


    • #3
      TOO high a ratio for 6 with od. I would use at least a 4.10
      You would have a good highyway speed if you could ever
      get up to speed.


      • #4
        Flashback is right on the money. Generally speaking, yes, a 3.54 could normally be considered way too high for a Champion six with or without overdrive, especially if you have hilly country. Even on flatland country, it might be quite a slug. I mentioned the Studebaker factory tests with the 1959 90hp 170 cid flathead six for a good reason. If you look at page 300 of the 59-64 chassis book, 3.54 is listed with sixes and V8, but the later chassis books don't break down what transmission options were available with which axle ratio, so it might have only been with the automatic. But, the factory did do tests at steady speeds to measure gas consumption, so even if not offered generally, a 3.54 was apparently 'do-able' on a Champion six

        However, a 57 Champion engine could be had in both straight shift and overdrive with a 3.54, part # 534788 in a F1 and W1 Scotsman 2 and 4 door sedans (not the wagon). In the non-Scotsman Champions, the 3.54 was reserved for Automatic Drive. In 1958, part# 1544503 3.54 was again available with the F1 and W1 Scotsman with overdrive, and for all Champion engined cars, standard and automatic drive except the Y1 long wheel base sedan (ie taxi) See Page 346 in the 55-58 chassis book.

        There is a 19% difference in horsepower, of course, in the pre-55 170 and the 55-58 185, but its only 6% in the 59-60 flathead from the earlier engine. If you are running shorter radial tires, and pre-55 engine has been rebuilt with an overbore making it a bit large displacement, or thinner gaskets for slightly higher compression, then the effective difference might well be negligible from the factory tests.

        Anyone out there with a 57-58 Scotsman 2 or 4 dr sedan with the original standard or overdrive transmission with the 3.54?