The problem with the stock shackles was that they were pinned to the bottom of the frame because of the weight of the sbc. The springs were at max compression so by adding a 2" longer shackle I ended up with a very nice shackle angle and got the springs off of the frame. I understand what you mean about getting a bad angle and bad ride, I will not try and deny that happens a lot with some setups, but in the case of mine and shawnb's truck it solved many issues.
WT