Rear-end ratio?

[BurtReynolds]

Hello,

I have 64, with D-code engine, 4-speed toploader, and 3.00:1 standard differential.
I'm thinking of upgrading my car with some kind of locking unit, and closer ratio rear.

I mainly drive in the city, sometimes longer distance (speed 60-70 mph), and maybe sometime I'll try even 1/4 mile (just for fun).

What kind of ratio you recommend, any experiences? Some one said that the ratio should be suitable for motor, is this true, or can I just take what I want.
How much the closer ratio will improve the torque, and the acceleration?
Can it be calculated somehow?

What kind of lock you recommend?

Is there something else I should chance, when I do this upgrade?

Thanks for your help!

 

[66_stang]

auburn 8.8 posi with 3.55 gears. Thats what im doing.

 

[BC61]

Gear ratio can increase the acceleration of the car within reason. With a stock engine and stock circumfrance tires I wouldn't go much past a 3.5:1.
The more gear you put in the vehicle the more rpm's it will turn at a given speed in relation to what it currently turns. 3.50's will turn about 3200-3500rpm @ 65-70mph. That's alot of rpm for a stock small block to run constantly at freeway speeds. High rpm's equals lots of gas, heat and possible wear & tear. If you don't do much freeway driving for any length of time something around 3.50's will work. If you do alot of freeway driving I'd stay around 3.20's. 3.20's should keep you at or just below 3000rpm at 70 mph.
If you run a plus size wheel and tire then you can run a bigger gear as the tire circumfrance will have an effect on final drive.