Basic setup Z6 block B7 head @ 16 psi. I had a B7 intake manifold with thermal gasket and with all the good things being said about the Z6 intake manifold I figure I give it a try. Installed without the thermal gasket but deleted all the coolant hoses for the throttle body and iacv. Ended up losing a mph in the 1/8th. Traction wasn't as good as the day with the B7 intake manifold but the weather was a lot cooler. Air fuel ratio in the mid 11s on both intake manifolds. So is it only a good upgrade for the NA guys ? Here's the slips for comparison. First set B7 intake. Pretty disappointed with it. I even left out putting a b16a throttle body on it to see what difference just the intake manifold makes.