Rear end gear question

[D-CEL]

I laughed when I read “gears that low”. I’ve been running (and recommending to friends) 4.10s in Mustangs for years. Most had the same view point, until they drive with them. I would say “low” gears starts at 4.88 and go up from there.( I once saw a set of 7.33s for a 9”)
Actually 4.10s are much easier to live with everyday. The added toque multiplication makes coming out of the hole a snap. You can just about dump the clutch without adding throttle and it won’t stall. No need to slide the clutch to get it rolling. They naturally idle thru parking lots at idle rpm. It’s just an all around good deal. They make the car snappy and ferocious….just like a Cobra should be.
The “4.10 is too much gear”myth was born in the days of 1-1 top gears, 5000 rpm max, hydraulic lifter motors and E-70-14 tires (25” tall).
That combo with 4.10s @ 65mph would have the motor was buzzing along at about 3600 rpm (73% of max)and a blinding top speed of 90mph. Dropping the gear all the way down to a 2.73 would put the 65 mph rpm @ about 2400, you could live with that every day. But at the expense of 35% less available torque (give or take) that is a huge number in a “torque challenged” small block car.
Times have changed.
The simple swap to an over driven 5spd makes all the difference. A .64 high gear and 4.10s puts the 65 mph rpm @ 2300. Add a set of 295-50-15s and it drops to 2195.

Jason