So, I have two brand new housings and I am trying to figure out which is the front and rear. They have different part numbers, but they aren't in the box with the numbers anymore. I can't see a visual difference between the two. Is there actually any difference? Does it matter which goes where?

 

there is an F or R stamp in the top.

 

^lmao, that was full of win right there.

 

Rotor housings? They're different? It must not be much of a difference, or maybe I'm just lucky. Oops...

 

the differences are emissions related more than anything else