You could build a nice 416 stroker for under $6000 if you don't use all the higher priced parts. I have a few hundred over $6K but I used the forged crank, H beam rods, Mahle pistons, custom cam and some other goodies. It runs great and has great street manners and has around 600HP.

416 stroker from Nick at Compu-flow. 11.14 in full street trim. Seems like a new best every time out.
11.06 open headers----so far!!