From the description of the type of performance you want, a conventional 5.3L or 6L with a custom cam would be a good bet. An engine can be cam'd for low end grunt, and peak hp at a desired redline.
A good guy to talk to is Chris Straub of Straub technologies. He does custom cam's for a lot of people.
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
Threaded Mode