You could do a basuc shortblock that would be good for 1000whp for 3k. You will have labor, gaskets and other expenses on top of that. I would think 5-6k for a basic deal with a clutch. If you were to add worked heads, cams springs, etc, that could double or tripple pretty quickly, depending on how extravagent you get with parts. Considering how often built motors fail, I lean more towards the keep it simple realm of the build. That will depend on your pocket book though. It might not hurt too badly to blow up a 3k shortblock, but it might hurt a whole lot to blow up a $15k motor.