how to tell a 5.3L compare to 6.0L

as title says, 5.3 vs 6.0L,, runs great, no problems.

mine is(i'm told) a 6.0L 2008 2500HD, 317# heads,iron block,, 4L80E trans.

question; did any 5.3s come factory with 317 heads???

and is it an LQ4 or LY6.

cant see rear of block,its up against the firewall in a 85 GN Buick(like 1/4") clearence.

its DBW throttle.

No 5.3 came with 317s stock. It could be an lq4 or lq9. Ly6 came with rectangle port heads. 823/821 casting. This is assuming the top end has not been changed.

Pull the front powersteering accesery brackets off block will b stamped on drivers side either 4.8/5.3. Or 6.0