What is the difference between pork chop sideburns and lamb sideburns?

There is no difference between "pork chop sideburns" and "lamb sideburns" – they are both names for the same style of sideburns.

The term "pork chop sideburns" is more commonly used, and it refers to a style of sideburns that are thick, wide, and extend horizontally from the ear to the cheek. This style is named after the shape of a pork chop, as they are typically cut in a similar shape.

"Lamb sideburns" is a less common term, but it also refers to the same style of sideburns. It is likely that the term "lamb" is used because lamb chops are also typically cut in a similar shape to this style of sideburns.

So, whether you call them "pork chop sideburns" or "lamb sideburns," you are referring to the same hairstyle.