Dumb move

I threw some 2 inch blocks in the rear of my 09 sport DC and now I feel a small vibration when I down shift the blocks were flat... I've done a little research and it seems I should have used the angled blocks I found some 2 degree shim for this and I was wondering how much degree I need to make it right ?

 

Every vehicle is gonna be different. You can also purchase a carrier bearing drop kit as well.

 

I ran 1.5 blocks on mine, slanted ones and got no vibration. I still have them if your interested, $30 shipped without u-bolts