I did a SPOA (spring over axle) myself the kit said 6 inch and I guess I got all 6 cause they say if you go over 6 inches you have drive shaft vibes cause its at too much of an angle .. you can get the SPOA perches pretty cheap $65 - $85 but then you have to get alot of other things like extended brake lines , a z bar or some other way to do your steering bar cause it doesnt work anymore , shock mounts , shocks , new U bolts cause the old ones are to cheap , of coarse tires and wheels .. then you dont have as much power as before so you get new T case gears .. boy it is alot , but worth it , to see the look on people faces on motor cycleswhen they come around a curve or over a hill where no vehicle aughta be , there you are , ha ha priceless