If you have not seen inside the intake manifold, here we cut open a LS1 intake.

The bottom is 3/16ths inch thick.
Notice the opening to ports 2 and 8 is smaller by 1 inch.

Runners are 12 1/2 X 2 inches

It is 2 inches from the bottom of intake to the runners.

Attached Files ls1intakeopen2.jpgls1intakeopen3.jpgls1intake.jpg

Team ZR-1
True Custom Performance Tuning
Teamzr1.com