Harley:
If you have the facilities to fabricate your own intake, brackets, pulleys, etc, you could put a supercharger from a GM 3800V6 on your 250 for around $500 in materials. Mine has a COMP H268 cam and Edelbrock 600 carb (another $600), but is stock otherwise. It has AWESOME TORQUE! from 1000 to 4000 rpm. The stock EFI would probably work better, especially for your application, but i didn't use it cause i just don't like electronics.
If you are interested, i would be glad to assist with intake drawings, tips, and "don't do's".
Good luck!
