grounds and voltage drop

[illestVillian]

Does grounding from the battery to the alternator mount count as the same as grounding from the battery to the engine? My battery to engine ground is tough to get to. I started my big 3 today,1/0 from the Alt to the battery, then started battery to engine ground but quit cause of back pain. That old ground wire is frayed that I tightened back up. Thinking it's that or not having the grounds matching 1/0 positive run I did. This is with no stereo playing. 14.4 volts sitting, then driving when I slow down it drops down to 11 volts.then stalled. Never happened before ever.