Katech and Halltech tested one of the first LSXR intakes on the Katech Superflow dyno used for the C6.R Race engines they built, and our 429 E85 motor gained 14 HP/ 20 lbs-ft. just swapping the intake out. The dyno below was done first at 12:1 CR and just swapping out the intake it went from 615 HP to 629. The 636 was with 13:1 CR, and prior to the 102mm Williams Performance Throttle body.
The LS3 needs more cam before any real bennys will be gleaned from this intake manifold.
Our LS7 motor is now at 650 HP/600 lbs-ft with the addition of the 102mm throttle body and 13:1 compression on a steady diet of E85.
Jim Hall