if this question is being posed (original posters question) regarding using 1ton shackles on a swb chassis, may i suggest that he uses standard 109 shackles instead, they are only 1/2" longer than the swb shackles which will be lots easier on the u.j.'s...

i intend doing this as i have a pair of tired parabolics on the front which makes my truck sit "nose down" and this trick should bring it back to close to level, i've a couple of friends that have already done this and not run into any u.j. problems yet