Those are floating pin rods with the flat tops..... So unless they are from a late 4.8 ( which the rod is a different length) those are L33 rods and pistons shown above.

4.8 has a 6.4" long rod as compared to the 5.3/6.0/6.2 length of 6.125"

 

Ok the reason i am changing is bc my pistons are junk and need to be replaced. I take it all l33 were 5.3?

 

L33 is the RPO code for the engine ( like LM7, LM4, LR4, whatever) and designates something specific, not a generalization. So yes, an L33 is a flat top piston equipped 243/799 headed 5.3.

 

Thanks for the help!