stock gear ratio question

[2manyprojects]

I need to know what the standard rear gear ratio was in a 69 C10, 6cyl powerglide?
I can get a free rear but don't want to drive 6 hours if it is what I have already. There is no one around that can check it for me.

[raycow]

The most common gear was 3.73, but other ratios were optional, from 3.07 to 4.10. I'm assuming your glove box plate is missing, or else you wouldn't be asking.

The best way to make sure of what you have would be to count your ratio directly.

Put matching marks on the pinion yoke and differential housing. Jack one rear wheel off the ground, put the transmission in neutral, and the parking brake off. Turn the wheel exactly TWO revolutions and count how many times the driveshaft turns, estimating any fractional turn as closely as possible. That number is your axle ratio.

If the wheel is difficult or impossible to turn, you may have posi. In that case, jack both rear wheels off the ground and turn either of them only ONE revolution. Count the driveshaft turns the same way as for an open rear.

Ray

[2manyprojects]

Thanks for the reply. My 67 has 3:73's . The rear I might get is in a 69 that belongs to a relative of a friend, but it is about a 6 hr drive away. I saw the glove box sticker for the 69 but didn't see any optional ratio listed. That's why I want to know what was standard with a automatic . The truck is trashed but has a good rear. I'm hoping for a highway gear to build for when I loose the 6 in the 67. Normally I would go with a overdrive but I already have a M20 Muncie 4spd sitting around.

[LONGHAIR]

The M20 is not the greatest pick for these trucks. First gear is not low enough and if you run a rear gear that is low enough to make it "drivable"...highway driving becomes an issue.
If you really want a car type 4 speed, one of the lower geared Super T-10s is far better.

[2manyprojects]

Originally Posted by LONGHAIR

The M20 is not the greatest pick for these trucks. First gear is not low enough and if you run a rear gear that is low enough to make it "drivable"...highway driving becomes an issue.
If you really want a car type 4 speed, one of the lower geared Super T-10s is far better.

Thanks for the input. I know my set up wont be completely ideal. I'm trying to put this one together with as little cash as possible. Later down the road I will probably go with the 3:73's and a overdrive. I already have the M20, it's a left over from one of my GTO's . I will be running a 454 built for low end torque it was originally going in my 65 C30 . I think that will help make up for the high first gear and 3:08's. It will also be turned into a short bed to drop some weight.