The modern Chrysler engines use variable runner active intakes controlled by a flapper valve to switch from long tube to short tube based on rpm. They are used on the 3.5L V6, 5.7L Hemi V8 (truck engine) and the 6.4L Hemi V8. All of the different runner lengths are cast into the intake and the flapper valve redirects the airflow. No need to trombone anything, just a simple flat plate air door is all that is needed with port injection at the heads.