Overdrive in Early A

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I hope this helped, and if I gave any info that wasn’t spot-on, I welcome folks who know more to correct me for the sake of accuracy.
I have one of those that I used to use. I found the splits a lil too far apart for a streeter, and I broke a few od gears in the learning process.
I switched to a Commando, and have had no more breakage.
I like this idea, and here is my 2cents;
Again, running 65=2400.
To use the Overdrive, (3.09-1.67-1.00-.73od)you would use 3.8s which rounds down to 3.73 which will get you 2400=66.8 mph/ close enough. The starter gear will be 3.09 x 3.73= 11.53, which, IMO is too low for street unless you have a slanty. But Second is 1.67 x 3.73=6.23, which, IMO is not enough for any SBM except the 360. This gear is just too far away for performance driving with the lower-torque designs. Like I said, I ran it behind my Hi-torque 367 with a 230/110* cam, for three years then finally moved on.

I switched to the Commando (3.09-1.92-1.40-1.00), I have run this since 2004 behind my 367 with quite a few different rear gears settling on 3.55s.
I have also run it behind a lo-compression 318 with gears down to 2.94s. With my taller tires I use the 2.94s to get 65= 2380..
This gets my 318 a starter gear of 3.09 x 2.94=9.08, a lil low, but I lived with it. Second gear is now 5.64, still low, but is a lil closer to first, and I didn't feel it so bad. The big deal is now in Third. Previously the split was .599 with the od, but now it is .729, which is way closer. Running the 318 up to 5000, the rpm drop is now to 3646 versus to 2995 with the overdrive. which is a difference of 650 rpm, which the short-stroke 318 really notices.
This 318 was my winter-engine, and I only drove this Commando combo One winter, but I really liked it. In the five or six winters, I did this, I used a manual trans about 3 times, the rest were with an A998 and a 2800Tc, and at least one of those winters was with 2.76s.. Maybe they both were; I really liked that combo.
Here is how those ratios stack up; first the od with 3.91s, then the Commando with 2.94s
12.08-6.53-3.91-2.85 overdrive, 65=2307
9.08-5.64-4.12-2.94 Commando, 65=2380
Notice how the Commando has a better third, to the od having a better second. Engine choice and build will be important.

To be truthful, you will likely find here on FABO, as many guys liking the A833od as not. If you got one, run it. If not, .............
 
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