Jason, I have a set of OME heavy springs, shocks and U-bolt flip kit. My '87 FJ60 was converted to the Toyota 1HZ diesel, which is also a heavy engine, plus I've got dual battery, ARB bumper and winch. I'm heavy enough that I added an extra main leaf in the front to the already 'heavy' spring pack. In the rear, I added two extra main leafs to the already heavy spring pack because I'm armored all around and have a 38 gal tank, and with a full load of gear for long trips the two leafs were needed but it rode really well. No shackle reversal, though, you'd have to get/fab that yourself. I'm not aware of a standard kit for this from OME. I just took them and the axles off because I'm going with new axle housings and new suspension for bigger tires. If interested PM me and I'll send pics. Would ship from 94568.
