360 Engine cranks but won't start

No, just one of the bolts that holding it to the firewall.
But you do have spark, i think the grounding issue is a dead end. :-)

I would started over as you did, rotate the engine until cyl 1 is at tdc, check that rotor in dist. Points toward cyl 1 spark plugwire. Try to crank, if nothing happens, turn distributor ccw(?) to advance timing. If you have turned 2 inches without action, turn it back 2 inches, exchange sparkplugwire 1 and 6 and try to crank. Try to advance ignition until cyl 1 and 6 fire... Then fix the rest of plugwires, start engine and adjust timing with strobe...

Good luck