What does “Where is my 40, homes?” mean?

Solution 1:

"homes" is almost certainly being used to mean "friend" or "buddy" It's a very common phrase among people speaking Mexican influenced English, so the Mexican accent makes sense.

It is unclear exactly what is meant by "40" in the context of the question. A "40" often refers to a 40 oz bottle of beer or malt liquor, so he might have been looking for that. Or maybe the second guy in the scene owed the speaker $40,000 for the fancy car.

Depending on the tone of voice and body language, "where is my 40, homes" could have been aggressive/threatening, indicating the speaker was upset that he didn't have his money.

Solution 2:

A "40" refers to a 40-ounce bottle of malt liquor. Buying a 40 is particularly popular in the ghetto because a 40 will get you the drunkest for the cheapest. Because of the clientele that 40's bring in, some grocery stores and liquor stores refuse to carry them.

"Homes" should be "Holmes," which is a colloquialism that started with Latinos and means the same thing "dude" means, meaning it can often be used in a way that means the person is a friend, but not necessarily. Just like you might say to a friend in a friendly way, "Hey, dude, what's up?" you could also say, "Hey, Holmes, what's up?" But you might likewise say to someone you don't know, "Hey, get out of my way, dude!" or instead say, "Hey, get out of my way, Holmes!"

I'd source this, but I don't really know how because the way I know what these things mean is by living life.