Which one do I want to put in a 56 F100? I just got back from the local Pick-Your-Part and they had several to choose from. There were several mid - late 70's XJ6 versions without LSD, There was an 88 model with LSD and an early - mid 70's XJ12 L with LSD. BTW the XJ12 L had some bitchin worn red leather bucket seats. I don't have any use or storage for those right now though. The 88 model had single coil springs on each side while all the earlier models had dual coil over shocks on each side. They want $250 +tax for the whole assembly so, I may just wait until the next half price weekend.