High volume fuel bowl question

[This old banshee]

Hey question regarding me oversized fuel bowls, is the volume increased due to being "wider width" bowls, or a deeper bowl. I am assuming they must be wider in both directions not depth. 

 The reason I ask as in my brain a deeper bowl is telling me it is useless as the fuel pick up still only extends the stock length, so regardless of capacity it would only draw the same volume as a stock carb.

 Would anybody have a photo of a stock bowl versus an after-market one with a side to side photo showing dimensions? 

Or I'm if I am missing something plainly obvious please explain