Torsion Bar Upgrade for '65 Barracuda Formula S
the bigger bars would be a great addition. these cars were undersprung from the factory so upping the spring rate is an excellent idea.
keep in mind that if you go above .920 you'll need good (read: expensive) shocks to control them.
unfortunately, nobody makes/repops .890's or really anything smaller than 1.03 these days. so you'll be looking for used or some NOS ones kicking around on a dusty shelf. firm feel makes custom sizes if you're will to drop that kind of coin.