well i tried this once on my datsun 120y, with no success mind u!, basically i tried to remove the rear spring( easy as, just jack up car, support blocks, then undo evrythng) then i flipped the spring over, Q? have u ever tried to turn a thick metal strap, which is curved, inside out? with my limited engineering gear avail at the time, i gave up. easy option, take a "U" bolt to ur local engineers, tell them that u want it X inches longer, and thy should b able to use a high tesile rod, threaded, shaped, sweet as, just need bloks, VIOLA! CAUTION: This is how we can do it here in nz, not sure weather u need a report from th engineer or wot, i kno tht in aus, it can b harder