The manifold really did not change. I just went through the 66-71 parts book. The tube changed in 69 from the 66 2538846 to the 2892815. But the indicator never changed part number. Stayed 2538849. Tube probably changed from the bolt on style to the press fit style that mopar did, but the shape probably the same. If some one has an original hemi stick they could post a pic and measurement.