[DavidPHumes]

Thanks guys.

The L33 is out of certain '05 Silverados. They are not very common and often get bought up (by people like me) as soon as they hit the market. They're advantageous over an iron block for multiple reasons:

- Lighter weight (obvious)
- Slightly higher CR (9.9:1 vs 9.5:1 of a standard 5.3)
- Stronger rods (don't know the facts here but it's what everyone says)
- Flat top pistons
- 862 casting heads (almost identical to 243 (Z06) heads)

I don't know about LSxs sounding bad. I like the sound just right. Sounds like a throaty V8 to me!