Dash indicator lights and head lights begin to flash slightly, dies

After the car runs for a bit, the dash indicator lights and head lights begin to flash slightly, dies, can't find a ground short anywhere.

Had the top block rebuilt, 1 and 2 were misfiring. Drove it first night, wouldn't start the next morning. Alternator was bad. Replaced Alternator. Runs for a bit than dash lights and head lights begin flashing. If I turn it off, won't start. Also speedometer stopped working first night, now jumps occasionally. Checked ground on alternator, they didn't have it tight. Tightened it, no real change.

Can't seem to see any other ground or wire that is loose. Any help would be great.