I have a 72' with a 350/(300 hsp) Turbo 350 tranny, 12 bolt posi ratio 4:11. I am not a drag racer.... I want to be able to enjoy street driving and also highway driving but still want to keep some level of performance.

Please advise,

-Jackie

3.08:1 - 3.42:1

I would suggest one of those or something in-between. If it's a daily driver or going to see a lot of highway, I would go with 3.08:1.

I have 4.11 in my street car, but I don't take it on a highway. I just run around town and if I'm going somewhere a little further, I take the scenic route. :D

The 3.08 would be best on the highway. The 3.42 is good all around, but you probably won't want to drive it more than a few hundred miles at a time with the 3.42.

Howabout a 3.23 or a 3.31? Or maybe a 3.36?

Here's my question.....what cam/stall are you running? If it's a race cam you'll probably want to step it down, otherwise expect the car to be a real pooch.

There is nothing for the 12 bolt between the 3.08 and 3.42.