Quote Originally Posted by Fast355 View Post
5.3l is somewhat weak in low-speed torque and I would put money on that Regal having a rear axle ratio in the mid to low 2s.
Not exactly the combination for a strong runner.
LS1 F-cars were a bit undergeared and the autos had 2.73.
Optional F-car gear with 5.7L LS1 & 4L60E was 3.231 on 25.6" tall tires, which was just about right for the LS1's power peak @ 5600RpM.
For the slightly lower power peak of the 5.3L V8s, 3.42 might be a better compromise between metro / urban & highway MpGs.
With a fully enabled Aussie operating system (patch), even 3.73 is not unreasonable.