Do the 5.3 engines in the 07 models have cathedral port heads? Do the 07's have the 58x reluctor wheel? Do the 08 5.3's have cathedral port heads? I wasnt sure with the new LS3 architecture what exactly has changed.
Thanks,
Daniel

 

From what I have read the 07's still use a GEN III based head with cathedral ports and intake but have a 58x reluctor wheel and new PCM. I haven't actually takin one apart though. The 08's are more then likely the same. I can't see them changing anything soon because the heads now work good on a 5.3L.

The L92/LS3 heads have the bigger valves and square ports and GM would have to put smaller valves to get them to work.