Which Torsion Bar?

When I needed new torsion bars for my 383 dart the advise I got here on the forum was at least 1" bars. I bought them from Firm Feel and it worked out good. Car is used for street, shows and cruise nights. I also found an engineering web site that sells some front suspension parts they designed for A bodies and on the site it said a good estimate for front spring rate was 10% of the front axel weight. I weighed the front axel of the dart and the spring rate of the 1" bars was 10%. The 1" has been perfect for the use of the car.