Well I never thought I'd say it ( Doghead is gonna S***) but that info ( Filter #'s) is the most basic and easiest info to find on this site, a simple search in the Deuce forum would have gotten you all the info you needed. I typed in "NAPA filters" and got all the info ( and then some ) needed to answer your question.
Yes every question has been asked before on this site and to a point I agree with your statement but this one is newbie basic 101, instead of FAQ maybe we need a Newbie forum, you know kinda like a kiddie wading pool where you learn the basics first.
To help answer your next question, the ldt holds 22qts of oil.,
The napa air filter will work but it really is to small and will cause restriction, below is picture of the napa ( left side ) and the stock air filter element ( that would be one on right side
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