The Forney 140 MIG uses a Tweco style torch and uses Tweco #1 consumables for <200A machines and Tweco #2 consumables for >200A machines.
The Forney 140 MIG uses an aluminum wound transformer.
Yes, although a 3/4″ cut will require patience and significant cleanup with this machine.
The ground cable for the Forney 700 P is flexible.
The Forney 700 P is 40A and will cut thicker material faster.