Recently restored our '72 Cutlass. Here are the specs

'65 425 Engine bored '030 over. 10.25:1 comp
Cam: JM 20-22 .496 lift int. .512 lift exh. 266/274 Duration 110 LSA
750cfm quad carb
stock intake
small valve cylinder heads (believe A or B stamped)
Fresh built TH400 trans.
2500 torque converter
18x8 inch wheels in front with 245/40 Tires
18x10 inch wheels in rear with 305/40 Tires

Now, my question concerns which rear gear would be best with my setup? Currently there is a 12-bolt chevy rear but I believe the gearing is 2.7 or less. I am keeping the 12-bolt so I was looking at getting either 3.55 or 3.73 gearing. Which of these would be best and why? What would I expect with each gear? I am mostly going to be driving 1 day per week on weekends or to cruise-ins/shows. No long highway driving.

Thanks,
Derrick

 

If you're not going to be racing the car (and I wouldn't expect you to with those tires) then I would go with the 3.55 or a 3.42. You should have plenty of torque and the 3.73 will only add to wheel spin.

 

thanks for the response