I had a K5 Blazer that was lifted when I bought it, it had 8 inch leaf springs, 2 inch blocks in the front and the rear had 3 blocks stacked on top of each other 2 4 inch blocks and one 3 inch block and a 3 inch body lift on top of all that. There is know way that I would ever stack all those blocks together in the rear end, and for a daily driver I wouldn't put blocks in the front end but for a off road truck I never had any problems with mine and I was beating on them with a built 327 with 4.88 gears in the diff's, turning 38inch Boggers and never had a problem.