[b-man]

Finding your rear gear ratio is easy as long as you’re able to jack up the rear of the car safely and get under it.

Mark one rear tire so you can count the rotations. Jack up that tire and leave the other on the ground.

Now mark the driveshaft yoke and rear end.

Turn the shaft and count the number of turns of the shaft needed to make the tire make two full revolutions. If the shaft turns 3-1/4 turns you surely have 3.23 gears, a little more than 3-1/2 turns then you have 3.55 gears. This assumes you have an open rear end, no limited slip or positraction.

If you have posi get both wheels off the ground and count the turns of the shaft do one full revolution of the tires, assuming the posi is in good working order.

You don’t need to look for codes or buy a PHS report to know your rear end gear ratio.

For a peppier takeoff get a Saginaw 4-speed with a lower first gear ratio than a Muncie or T-10. The Saginaw with a 3-something first gear will be less able to withstand abuse but they’re fine for normal driving. Higher numerical first gears are inherently weaker than lower numerical first gears as a general rule no mattter what make of transmission.