Selection of Torque Converter and Rear Gears for Hot 340

That would be the size tire I’d suggest for a B body since the rear of the car weight would just out a damper on the smaller tire. It wouldn’t grip as well unless you really have the weight distribution & suspension worked out.

I run did the same tire on my ‘79 Magnum. The extra width, as small as it is combined with tire height is a big difference.