The precise placement of about (like just, only, etc.) is often variable, particularly in casual speech. It could appear after talk, or after hours, in OP's example - either of which would sound more "natural" to most people than the actual example.
We're always being told that "Don't end a sentence with a preposition" is a discredited maxim, but the fact of the matter is people do think that more often than they should - so perhaps that's what prompted OP to go for the least pleasing placement of the preposition.
In practice, the main thing is not to let the preposition get too far away from the specific word it's associated with - in this case, "talk about". You wouldn't, for example, want to say...
?It is a subject which I could talk to the chairmain and the board of directors for hours about.