400hp from a D series engine is possible. and it wouldn't surprise me if it hasn't already been done.
However you won't do it with only $1800, and theres no way it will be a streetable engine, or for that matter a relaible race engine.
As a project for an enginer and profesinal engine builder with to much time and money on thier hands its a pluasible idea.
For a kid with a dream, it will remian a dream.
