1.14" Sway Away Torsion Bars
I guess my question really is: How stiff should 1.14" t-bars be when I bounce the fender?
To answer this first- bouncing on the fender is a ridiculous and nearly meaningless way to test torsion bar stiffness.
The blown out shocks absolutely effect this, because the damping rate of the shock also determines how far the suspension will travel when you "bounce" it. Ride height will have an even bigger effect. If the car is lowered, and you're still using stock height bump stops, you're probably bottoming the suspension out on the bump stops. Especially with 318 torsion bars. Which pretty much ruins your "test". The 318 bars will seem really stiff if you bottom out the suspension on the bump stops mid-travel.
Sway Away has a torsion bar rate calculator right on their website, you just have to know how to use it.
Torsion Bar Wheel Rate Calculator - Sway-A-Way | Racing Technology
The outer diameter is 1.14" in your case. The A-body bars are solid, so, the inside diameter is 0. The effective length of the bar is ~33.8". As described that's the length of the bar 1/2 to 2/3 up the radius to the hex end, where the bar necks down. The overall length is 35.8, measuring radius to radius knocks about 1" off each end, so, ~33.8". Last is the length of the lower control arm, that's middle of ball joint to the middle of the pivot pin. On an A-body that's 12.875".
So, plug all that in and you get 332 lbs/in. If you get the same result from those bars as you do your 318 bars, you did something wrong (like, it's sitting on the bumpstops).
You can also email Sway-Away, they were very helpful when I contacted them about some B-body bars I bought second hand. If you sent them the LCA length, they'll calculate the wheel rate for you because they have the rest of the dimensions. I'm pretty sure they'll tell you the 1.14" A-body bars are pretty close to 332 lbs/in, but you don't have to believe me if you don't want to.