Are you starting out with anything, block, heads etc? If you are not 6k can be gone pretty quickly especially if you use good parts. Will it be mostly a driver or will you be racing it a fair amount?
One of the shops that comes to mind is DG machine, Dale Green is a good guy and I have heard nothing but good about them. Works with racers a lot (if you call tell him someone with the NPSA recommended them).
I know of some good "budget" shops that could handle the build too. It really depends on your goals and desired use. I will say avoid Eagle parts in anything but a serious budget project.