Bump stop without clearance - cause of squeaking?
Make sure you take the weight off the suspension before you turn the adjusters any, and it would probably help to use some WD-40 or penetrating oil on them before you turn them any.
These cars were dramatically undersprung from the factory to begin with. Personally, I wouldn't use anything less than a 1" diameter torsion bar on any A-body. PST sells a 1.03" bar that's pretty popular, I don't know about getting parts to the Netherlands. @BergmanAutoCraft also sells some 1.08's (as well as all kinds of suspension goodies for better handling) although that's getting into handling car territory. The factory rates were sub 100 lb/in, most modern cars are in the 200+ lb/in range. A 1.03" is around 215 lb/in, so quite a bit more than factory (which was VERY low) but still less than a modern sports car. Basically commuter car rates. My '74 Duster (demon clone) is a daily driver set up for autoX and I run 1.12" bars with a 300 lb/in rate.
Keep in mind too that your current ride quality is much stiffer than factory, because you're on the bump stops all the time. A 1.03" bar would likely result in a softer ride than what you've got now.
If the UCA's are newer they may be ok. If the LCA bushings haven't been changed recently, or you don't know their history, I would replace those now especially if you're doing the torsion bars and lower ball joints, because you'll have everything apart to replace the LCA bushings. If they look like the rest of the suspension in that picture then they're likely toast.
Make sure you take the weight off the suspension before you turn the adjusters any, and it would probably help to use some WD-40 or penetrating oil on them before you turn them any.
These cars were dramatically undersprung from the factory to begin with. Personally, I wouldn't use anything less than a 1" diameter torsion bar on any A-body. PST sells a 1.03" bar that's pretty popular, I don't know about getting parts to the Netherlands. @BergmanAutoCraft also sells some 1.08's (as well as all kinds of suspension goodies for better handling) although that's getting into handling car territory. The factory rates were sub 100 lb/in, most modern cars are in the 200+ lb/in range. A 1.03" is around 215 lb/in, so quite a bit more than factory (which was VERY low) but still less than a modern sports car. Basically commuter car rates. My '74 Duster (demon clone) is a daily driver set up for autoX and I run 1.12" bars with a 300 lb/in rate.
Keep in mind too that your current ride quality is much stiffer than factory, because you're on the bump stops all the time. A 1.03" bar would likely result in a softer ride than what you've got now.
If the UCA's are newer they may be ok. If the LCA bushings haven't been changed recently, or you don't know their history, I would replace those now especially if you're doing the torsion bars and lower ball joints, because you'll have everything apart to replace the LCA bushings. If they look like the rest of the suspension in that picture then they're likely toast.