Does not start, engine turns over slowly then stops

Bought car from insurance auction. Noticed timing chain was loose and wasn't able to turn engine with plugs in. Inspected valves, replaced timing chains, and starter. Car turns over slowly then stops, then can try to crank again and same thing. Put a booster on it and when the battery had 13.2 volts it would spin over decent and attempt to start then voltage would drop to about 12.3 volts possible ground issue? Something I'm overlooking?

Update: replaced ground car turn over better and tries to start but wont ever start.