I don’t know what’s left under a hood that your average joe could tinker with, I’m not very “automovitally inclined”.
Now, my dad could buy an old junker for maybe 50 to 100 bucks, do some fine tuning on it and sell it for 300. Never got the gift he had what way. A few of the bros picked it up, tho.
I can change oil, brake pads, basic stuff. That’s it. Used to change out head gaskets and starters back in the day but no more. Make too much money to mess with the stuff that will void my warranty - lol.