Kinda wish you didn't remind me that I need to replace mine... Lol
Now there was a time many years ago, that my buddy (yeah, I actually had one back then....). Anyways, he romped on the gas, and ended up tweaking the crap out of his RR spring. Looked like a huge "S". Front of the leaf raised, and the back lowered. He only had a mono leaf, so it was really obvious. Made the whole thing lean right. So, I'll take a guess its the leaf springs, like some of the other guys have. Time for a tape measure.....