On the 7mgte the exhaust gases leave the head and go into the manifold then into the exhaust turbo spooling it and then out through the elbow and down pipe. By blocking what I think you are talking about you would make a exhaust plug. You can still get the pacesetter or obx for the 7mge but they require modification and I don't really believe it is worth the hassle for the min. gains. I did mine a while ago in exhaust wrap since you can no longer use the heat shields.
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