First of all 14 x 12 volt optimas = 168 volts. 44 * 3.2 volt TS = 140 volts. Hope that is not an issue.
Interconnecting bars are available where you bought your batteries I expect.
How do you get 80volts and 50 amps? I suspect both numbers are low....???? Go to your local welding supply store and buy 2/0 welding cable and lugs with suitable hole sizes for connections. You may need to borrow/rent/buy a crimper.
As above...2/0 welding cable.
Just confused about your pack voltage and expected current draw. You should expect several hundred amps to get rolling and then perhaps as low as 50 for maintaining lower speeds. 80 volts??