Posi unit difference

[super sport]

Im currently working on a 62 convertible " SS " 409 QB and i have a 3.70 posi . what is the difference between the 3.08 , 3.36 , 3.55 , 3.70 and the ,4.11 units as far as performance.

 

[models916]

Multiply

Rear gear ratio multiplies the torque. 411 has more rear wheel torque than a 308 at a cost of RPM and gas millage and wear. Determine how you are using the car and go from there. I have a 411 with T400 in my 62 Belair.

 

[jim_ss409]

Here's the 1/4 mile results from a 1998 Car Craft article comparing various ratios.
3.00:1 = 13.75
3.50:1 = 13.40
4.11:1 = 13.18
4.57:1 = 13.15
I'm missing the last page of the article but I think the car developed a high speed miss with the 4.57 gears.