While I've never had an issue with axle wrap on my K5 I can tell you a little story about a rented Astro van I drove once....Lets just put it this way, the van was loaded with clowns I work with and there was another van loaded with the rest of the clowns I work with in the other lane. After some initial smack talking I shift the trans into neutral to rev up the engine. Light turns green and I floor it with the trans still in neutral. Needless to say I yanked the shifter to low with the engine spinning at it's 3500 rpm no load limit. I have never felt anything like that before or since. Those mono leaf springs on an astro are pretty flexy as it wrapped up like a piece of wet spaghetti. It hit so hard the tires actually hit/rubbed the front of the wheel openings. Black tire marks on silver paint were not hard to miss. It sounded like a friggen gun went off under the van. All the back tires did was bounce....
We all laughed our butts off when we finally stopped and saw the rubber on the paint. (Hint this is why you don't buy used rental cars)
Typical spring/axle wrap forces the front side of the spring up due to the pinion gear trying to climb up the ring gear. This forces the spring into an "S" shaped, but laying on its side. By forcing the spring up, it will forcibly come back down to try to get back to its original shape. Hence the bounce. Blocks in the rear aggrevate this by placing the spring further from the axle and allowing more leverage to be placed on the spring.
Even still, with a shackle flip and soft springs you can still get spring wrap. Best way to elimnate it is some type of anti-wrap bar that stops the upward motion of the axle under a hard launch.
