Lance,

If you can make it like that, and its really pretty constant cross section area between the inlet throat and the engine, then it should be fine. These engines are pretty tolerant, as long as you give them halfway decent airflow.

The only issue, which might just be the simplification in the drawing, is that you dont want any convex sharp corners in the duct, they should be smoothed out.

For example, the concave corner between the back of the spike and the starter is fine, but the sharp convex corner on the outer wall where it goes from the taper to the cylinder should be blended.

Bob