Rear end gear ratios

[Salyers890]

Here's the new dilemma - my brake adjustment screw on my 76 midget is frozen in position (broke the head off with the correct tool) i've tried everything and it looks like i'm just going to break the whole shaft off if i go any further. i have to take the axle shaft out to get that part off, and i'm pretty sure i have a good one laying around on one of my 4 rear end assemblies.
I read about the 3:9 and the 4:22 gear ratios for the rear ends on these cars, but as a newbie. . what does that mean? which is more desireable? how do i know which is which? since i'm going to have the axle shaft out, i may as well find out which i have in there and put the best one i have in my car. . . . thanks guys

mike

 

[aeronca65t]

All else being equal, the 3.9 is better for a street car. Look at the condition of the gears and be sure there are no nicks or obvious wear on the gear teeth.
The 3.9 will allow more "releaxed" crusing since the engine will spin less.
With the car in 4th gear, the 3.9 ratio will cause the engine to turn 3.9 turns for every turn of the road-wheel. The 4.22 will cause the engine to turn 4.22 turns per road-wheel turn in 4th.
The Mossmotors.com pages have a picture of the differential with numbers of teeth on the gears for the different ratios.

 

[Salyers890]

thanks, checking out moss now - appreciated