Just grab the distributor and turn it a good 1" counter-clockwise. If that doesn't start, turn it the other way. Once it starts, move it around to where it runs best. This will give you a running engine so you can use a timing light.
If it still won't start, you (or builder?) need to go back and check cam timing, firing order, valve lash, etc, Getting an engine from a professional builder in this condition is making me nervous.
Good luck,
Brian
P.S. Please stop grinding the starter. You cannot imagine the damage it's causing. When it starts, run it for 15-20 minutes at 2,000 RPM or higher to break in the camshaft and check for
oil pressure, leaks, etc..