Is there any easy way to identify a 5.3 from a 4.8 in a picture? There's a 5.3 on ebay I'm looking into bidding on, but I wanna make sure it's a 5.3, not a 4.8. Any help would be great!

 

Nope. You'd have to inspect the pistons to tell (5.3 dished, 4.8 flat top)

Just make sure you are buying from a very reputable seller. I just recently read about a guy on ls1tech who bought a supposed 6.0L, comes to find out it was really a 5.3 that they had put the vortec 6000 covers on!