Readily as in call up a vendor and buy them, yes that's exactly what I mean. Unfortuantly there is no one making anything any bigger than the 1.12 maybe 1.18 any more. Mopar used to make a 1.22, which is the biggest you can stuff in to the factory sockets, but they were discontinued many years ago. They still pop up now and again on web boards and auction sites, but not often. The only place I'm positive is making t-bars is Firm Feel. Certainly someone else is making them as well since there are other retailers, but I don't know their source and they also are limiting themselves to the 1.12 to 1.18 range.
Looking at t-bars rates, they are a direct correlation to the wheel rate, so a 200# torsion bar is 200# wheel rate. By comparison, your 750# Mach 1 springs may have only put 400# of force into the wheel based on the geometric stack up. As far as what rate is best, that kind of depends. The serious autocross guys all use 1.22 bars. However, XV's research showed that 1.12 for small block and 1.18 for big blocks were the best all around combination for stepped up performance, handling, and ride. If you do open track days, the 1.12 will get the job done. If your autocrossing, you will be leaving something on the table, by comparison.
A few vendors you want to familiarize yourself with in regards to suspension parts; Firm Feel, XV Motorsports, and Hotchkis. All offer component variations on the stock mopar design. Firm Feel and Hotchkis use and endorse Bilstein shocks, XV uses custom valved Afcos. All have slightly different approaches on their improvements, but all offer them as packages that will really wake up how your car feels. All have web sites you can browse.
