the T/A is a great street tire
Compared to a hockey puck, maybe? Compared to anything else, NO.
The world in which BFG T/A's are a "great" street tire doesn't exist anymore. And hasn't for at least a good 20 years. Probably more than that even. They may be one of the only tires available in the right sizes for a 14" rim on these cars, but that doesn't make them great. Compared to more modern offerings, they're mediocre at best.
Unfortunately, for a 14" rim there aren't many, if ANY, other options. But if you give up on the 14" rims and come over to the dark side, you'll find these cars can actually do pretty well in the handling department when you start with tires that were designed in the current century.
You need to get an alignment for radial tires. Most shops will punch the year, make and model into their computer and set the alignment to those specs.
Those specs are for a bias ply tire.
I tried this at work (Ford service department). I punched in 1968 Barracuda and it gave the factory specs. Those specs were the same, 40 year old specs, from the 1968 Plymouth service manual. Specs for a bias ply tire.
Absolutely true. If you enter any of our mopars into the computer at an alignment shop you will get the factory alignment specs, which are for bias ply tires. Depending on the shop, you may have a hard time talking them into doing something other than what the computer says. Some places just won't do anything else, even when you tell them those specs were intended for bias ply tires.
Regardless, the factory alignment specs for these cars are a disaster for radial tires. The factory specs call for positive camber and negative caster, which is a flat out nightmare for radial tires. What you want is something along the lines of -.25º to -.5º camber, +3º caster (or as close as you can get to it), and 1/16" to 1/8" toe in. If you need something in writing for the shop, check out this skosh chart. The above specs are a combination of the recommendations here, with the stock power steering you can run as much positive caster as you can get. With the stock upper control arms and bushings that's probably less than +3º, but that will depend on ride height. With offset bushings and stock UCA's +3º is pretty doable, and it will really help with handling and steering. Even the "granny" specs listed below are a huge improvement over the stock specs.