What was the first year for the L33?

 

If I'm not mistaken it was 03 or 04. I think it first started out in the SSR

 

How long does it take for these 5.3 H.O engines take to break in because I have about 9000 mi. on mine and now it seems to be getting faster. Just recently I noticed the tires will spin on a first gear downshift from about a 30-40 roll when before it never would. The only mods I have are a Superchips, magnaflow and a K&N cai.

 

I was thinking Silverado's didn't get them till '04, did 03's have them also?

 

2005 is the first year for the K1500. ECSB 4x4 only.