?Respectfully Request explanation of how/what this kit rod b engine fuel pump works/does?

Go to mymopar.com and download a factory service manual. Look at the engine cut away.

In a nut shell the cam has an ecentric on it. The pushrod rides on that ecentric and pushes the fuel pump lever to activate the fuel pump.

I'm not a BB guy so others might need to correct me but I'm about 90% sure what I said is correct.

BTW as I understand it it is not easy to replace with the engine installed due to downword angle of the hole it rides in.

Some thick assembly lube in the home IIRC will hold it in place long enough to get the pump on.