beau.

Guys-
Just picked up a Gen IV ls truck motor yesterday as a budget replacement for my Camaro's grenaded LS1 (pic 1&2). This is the beginning of a budget turbo build and I don't want to pull the heads if I don't have to. I've read enough threads to confuse me about what block this could possibly be, but more importantly (or relevant) whether it has AFM. I was told it was a 5.3 that came out of a 2011 with 160k (pic 3). The block came with 243's (pic 4), a flat valley cover (pic 5 & 6), and cast # is 12576177 (pic 7) which comes up as either an LMG, LY5, or L20. If we assume the seller was accurate in that this motor did come out of a 2011, then it would be an LMG or an L20, not an LY5. Looking through the aggregated information provided by Summit and some others, this block should have AFM. I did pull the valley (pic) and didn't see any garbage attached to the bottom of the valley cover for AFM so I'm thinking this motor is actually a L20 (4.8l) and not a 5.3l as advertised since it seemingly doesn't have AFM and L20's didn't come with AFM. Ultimately what I'm looking for from you guys is for you to tell me that this motor does NOT have AFM, that I do NOT need to pull the heads, and to push some air through the motor ASAP. Thoughts?
-Beau

G Atsma

You engine does NOT have AFM/DOD. 4.8 and 5.3 shared blocks as the only difference is the stroke.

01FormulaTA

iTrader: (20)

All Gen IV 5.3 have AFM from the factory, you have a 4.8...does it have VVT? Can you post a pic of the timing cover? If it doesn't have VVT its an LY2 4.8, if it does have VVT then it is an L20 4.8

no need to even pull valley covers in the future....if it looks like the cover on the left then it has AFM, if its smooth then no AFM...

beau.

Awesome, thanks guys.

This is the best pic i have as of now:

01FormulaTA

iTrader: (20)

thats a VVT timing Cover, so you have a Gen IV L20 4.8

beau.

Thanks for the help!
-Beau