Electric Shift Hp Gear difference?

I may have asked this question in years gone by... BUT... unfortunately I'm at the age (I Think) where my memory wanders, drifts, goes next-door or something!
I need to know which is which... Hp & Part #

Anyhow, I've come across the gears pictured below. The diameter of the gears are the same... BUT:

One gear has the rear edges of the gear level with the plain smooth finish of the gear.
This gear has 20 teeth.

The other gear has the rear edges slightly higher then the plain smooth finish of the gear.
This gear has 21 teeth.
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http://i124.photobucket.com/albums/p2/OMC-Joe/Gearcase Items/40-75ElecShGearsgrp-2_zpsa5f6a536.jpg

I am sitting here holding a NOS 308274 gear in my hand. It has 23 (raised) teeth

40hp gear ratio is 12:21
V4 gear ratio is 20:23.

fdrgator said:

I am sitting here holding a NOS 308274 gear in my hand. It has 23 (raised) teeth.
40hp gear ratio is 12:21....... V4 gear ratio is 20:23.

Click to expand...

Thank you Gator... Much appreciated. (Joe)