SS springs & sliders...
The ones shown above are Calvert made sliders, the arrow does indeed indicate the front. If you go to the calvert page and click on the picture of the sliders (it's giant!) you can see the stamped markings on them for the front and for the slider eye position. Calvert Leaf Spring Sliders [SL-300CR] - $189.00 : The Leader In Leaf Spring Innovation, - Calvert Racing
The idea is that the slider track should be parallel to the angle of the spring- so if you draw a line through the spring eyes the track should be parallel to that line. Whatever angle is on the spring should be on the track. If the angle on the track matches the angle on the springs then the angle of the spring doesn't change even when the spring is moving back and forth under load. This is a little info on the spring sliders I found, sorry for the size of the image. It spends a lot of time talking about having the springs toed in, which changes how the geometry works on corner exits, but that part isn't really relevant to A-bodies as the springs are parallel to the center line. But it also covers the angle of the slider tracks. I'm pretty sure the application of the image is circle track, but I'm not positive.
If you squint really hard in the image I posted above you can see there's a recommended angle for the rear springs. It shows a measurement of 6.5" to the bottom of the front eye and 14" to the middle of the rear eye. If you add the inch to go center to center, do some math, you come up with an angle of 6.8*. The stock mounting angle is a little shallower than that. The actual dimensions will change with the ride height, so, the arch of the spring and height of the rear tire, but the angle is the important part. On my car for example, with the sliders mounted flat, the front measurement is 7.5", the rear measurement is 15". Correcting that to center eye to center eye, I actually get the same angle as the picture, 6.8*. So, a notch on my car wouldn't necessarily be a good idea. But I use an offset front hanger, and it actually doesn't put the eye in the same vertical location as a stock hanger, so, other cars may be different.
On that note, if you're using a Hotchkis front hanger, or an aftermarket hanger with a 1" lowering location for the front spring eye, you may need a notch to restore that geometry.
Younggun2.0 did a notch with his sliders (and 3" relocation). You could add some angle to this operation pretty easily.
The ones shown above are Calvert made sliders, the arrow does indeed indicate the front. If you go to the calvert page and click on the picture of the sliders (it's giant!) you can see the stamped markings on them for the front and for the slider eye position. Calvert Leaf Spring Sliders [SL-300CR] - $189.00 : The Leader In Leaf Spring Innovation, - Calvert Racing
The idea is that the slider track should be parallel to the angle of the spring- so if you draw a line through the spring eyes the track should be parallel to that line. Whatever angle is on the spring should be on the track. If the angle on the track matches the angle on the springs then the angle of the spring doesn't change even when the spring is moving back and forth under load. This is a little info on the spring sliders I found, sorry for the size of the image. It spends a lot of time talking about having the springs toed in, which changes how the geometry works on corner exits, but that part isn't really relevant to A-bodies as the springs are parallel to the center line. But it also covers the angle of the slider tracks. I'm pretty sure the application of the image is circle track, but I'm not positive.
If you squint really hard in the image I posted above you can see there's a recommended angle for the rear springs. It shows a measurement of 6.5" to the bottom of the front eye and 14" to the middle of the rear eye. If you add the inch to go center to center, do some math, you come up with an angle of 6.8*. The stock mounting angle is a little shallower than that. The actual dimensions will change with the ride height, so, the arch of the spring and height of the rear tire, but the angle is the important part. On my car for example, with the sliders mounted flat, the front measurement is 7.5", the rear measurement is 15". Correcting that to center eye to center eye, I actually get the same angle as the picture, 6.8*. So, a notch on my car wouldn't necessarily be a good idea. But I use an offset front hanger, and it actually doesn't put the eye in the same vertical location as a stock hanger, so, other cars may be different.
On that note, if you're using a Hotchkis front hanger, or an aftermarket hanger with a 1" lowering location for the front spring eye, you may need a notch to restore that geometry.
Younggun2.0 did a notch with his sliders (and 3" relocation). You could add some angle to this operation pretty easily.