How in HECK to you figure HP on a B&S engine?

Picked up 4 old lawnmowers the other day, plus the 2 junkers I have. My intention LOLOL is to get one going for "crap" mowing in the weeds, and maybe another "the best" engine might try and build an outboard conversion with an old lower unit. "We'll see"

So these all have the same series types of numbers, and I can find various things on the internet EXCEPT the specs as to CID (or CC) and HP

Example
10T502-0457-E1

Found the operator manual and parts manual at B&S but no HP rating