a new mod i did not know about til tonight

Badd GT said:
this is NOT a spacer that goes between the upper & lower.

this is a 1 inch spacer that goes between the T.B. & upper.
it also has grooves cut into it to create a swirling effect.

If you believe that, then I have a few dozen "Tornado" intake inserts to sell you! :)

Ask any aerodynamics designer -- there's no way any "swirl effect" would exist (even if the grooves did anything besides slightly disturb the boundary layer flow near the throttle valve) after making the right angle turn down into the plenum, over to individual runners, back up, over, and down the runner into the intake port, *then* through the narrow, high-velocity annular gap when the intake valve lifts. The *only* swirl effect is that which Ford already designed into the intake valve/combustion chamber.

Save yur bux.