Does anyone have input on triming the runners of the factory magnum barrel intake? Mopar Muscle had an article about doing this but I don't remember how much to remove. How much power will this add?

Trimming the runners changes the "tuned length" and increases the tuned RPM. The shorter runners will wnt to make peak torque at a higher RPM and flow a bit better.

Hughes website has a article on this with more specifics.

The trimming modification needs to be matched with a hotter cam for benefit... if the manifold is trimmed with the stock cam, the two will be mismatched and the engine may lose performance.