You can find a lot of odometers for Assetto Corsa, but my choice was focused on this Mod Initial D Arcade Tachometer 2.2 for two reasons: in one package there are 5 odometers and their look is nice and nice.

It is downloadable free here:

 Initial D Arcade HUD | RaceDepartment 

You need to download Custom Shaders Patch to work properly.

The zipped installation file takes up only 3.5 Mb and, after downloading it, just move it to Content Manager (page with Drive highlighted) with a drag&drop. Content Manager will take care of putting the folders and files where they belong.

In Content Manager you can find it in SETTINGS

All options appear.

An impressive number of options allow you to modify

• the theme by changing the number
• unit of measurement: Kmh or Mph
• night vision
• lights
• pedal
• background
• position
• width and height
• etc

Here are the odometers listed with the number you can edit in Content Manager

7

6

5

4

3

On the author's "Vegetable Tsai" resource page

Resources by Vegetable Tsai | RaceDepartment 

I suggest you to download these mods because besides being free they are HUD variants and contain other gauges

There you will find the D Extra package with these gadgets:

D Advantage

It signals the advantage in meters over the car following you or the gap from the car in front of you.

D Driver

It writes down the name of the driver and the type of car and the position of those ahead or behind you.

D Lap time

Current lap time

D Map

Writes the number of the lap you are running.

D Records

Best time, last time, lap difference on best lap

Extra Settings

Allows you to modify the parameters of the gauges

Conclusions

Great job, very visually pleasing, useful and intuitive. Another Mod must have.