Did you do any recent work on your starter circuit? A hot starter circuit increases resistance which leads to a hard/no start. I'd first check the connections to the solenoid. Are they tight? Next check the starter wire heat shield tube. Is it attached to the correct location on the back of the block? See the attached PDF. If it's attached to location "B", then it's right next to the exhaust manifold. Make sure it is attached to location "A". Finally, closely inspect your positive battery cable for any issues.
