Which Axle Ratio Should I Go With?

[PxTx]

I've often wondered why a double OD trans is chosen when engineering a car. Seems like a 2.73-3.08 rear ratio would be best to keep drive shaft speeds down, then lowering the ratios in the transmission to get the desired gear multiplication.

My sister has a 300hp 69 Camaro. It has a 3.08 gear with a glide originally and she stepped up to 3.73. The car was a little more responsive. She never drag raced with the 3.08, but with the 3.73 the car turned a 15.01 in street form. We both drove the car and this was the best time. There really wan't much to make up in driver error.

Unhappy with that time, she then chose to install a 700r4. With nothing else changed. She then drove the car 14.2@98 (pretty sure that's what the MPH was). Not only was she happy with the results at the track, it really became more drivable. The low 1st gear in the 700r4 makes acceleration fun. I don't think the shift to 2nd is too wide.

I would strongly suggest considerign this trans. We took one form a 1992 Chevy van, simply slid the crossmember for the trans back and installed a shorter drive shaft. Still using the glide steering linkage on the column. Low gear is regular Drive. Great combination!

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My 5th generation Camaro came with 3.45s and I put 4.10s in that, but having a 6 speed with two overdrive gears is nice.

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[Survivor 69/Z28]

I do not mean to go against the grain here. But sounds to me like you are on a budget and would like to keep your car stock in appearance. In that case I would change the gears to 3.55 or 3.73. That will give you a seat of the pants kick plus it will keep your car looking all original.
Then I would also of course have it fine tuned. Then if you are wanting a little more. Install a free flowing exhaust system.