I did some intake dyno testing early last year on my 527 bracket motor with Indy SR M.W. size ports, I tested a 440-3 with a 9375HP Dominator on it and then swap that intake to a 440-2 (both unported) and the 440-2 with the two inch tapeered adapter and the same carb. with no changes made around twenty more HP. I added a two inch phenolic spacer to the top of the adapter and pick up some more power I did not try the phenolic spacer on the 440-3 nor did I try the Wilson 1.5 inch reversion spacer I have I will try that at the track, hopefully soon Monte has pointed out that when using a tapeed adapter on a 4150 manifold and not using a comparable spacer under the carb on a domintor manifold that you are not testing apples to apples becuase of the increased phelum volume do to the adapter on the 4150 manifold Dominic, are you going testing soon? If so I have a low deck M1 single plane dominator intake with several spacers and the Wilson reversion spacer if you wanted to test them at the track the same day to solve this dilema Call me if you do want to try that