Time for new rear tires questions

BFG T/A's were good tires for their day. Which was almost 40 years ago.

Compared to the BFG KDW2's I have on my Duster, they might as well be hockey pucks. Modern tire designs and compounds are light years ahead of the technology that went into the T/A. There are worse tires out there for sure, but the T/A is just your basic low to mid-range tire.

If the rest of your suspension is the basic low to mid-range stock stuff, they're ok. You're matching 40+ year old suspension technology with 40 year old tire technology, and you'll get the same performance as 40 years ago. But by today's standards, that's pretty poor. Start upgrading your suspension to have a more capable car, and you'll need to upgrade the tires as well.

As far as rims, you'll need to know whether you have the 5x4" bolt pattern or 5x4.5". Stock would be 5x4" for a '68. There was a company making SBP rims in 17" and 18", but I haven't looked for them recently as all of my cars are 5x4.5" or will be before they see the road. 17x8" all the way around would be a decent way to go, you could run 255/45/17's all the way around. You'd want 5.3-5.4" backspace up front, and about 4.5-4.75" backspace in the rear. In the front you're limited by the tie rod end, which gets usually to be an issue at around 5.5-5.6" of backspace on a 17x8.