6 inch rear suspension ?

I'm tryin to figure out the cheapest rear 6 inch lift on my 78 k10 with out using blocks.I do alot of trail runs with this truck so I need a good flexible setup any advice would be appreciated.  

Do a full leaf pack respring.My buddies 76 k20 has  this and it fantastic in mud and on trails.
He say that this way the lift is done right and not a pos with blocks.
By the way, his trucks a 76 that has a 454 bored out,14 bolt rear,dana 44 front and 37 super swamper tsl's.  
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There really is no "cheap" way to do it right. I run 6" blocks in my truck with 3" lift rear springs (custom built set), and I have notta problem with axle wrap, wheel hop or any bad new. I'm not saying this is the best and I'm not saying to go this route because it normally would have major problems but I lucked out this go round. Its still flexes like you wouldn't believe too. I would recommend going with longer leave springs and if its just an offroad rig you can ditch the overload spring on the bottom and that will give you a little more flex. Another thing to keep in mind is if you plan to have a set built for flexing, go with a thinner spring than what you have now. I had a 83 Blazer with 8" lift and 35s and my tires would rub the inner fenderwells on the rear. Talk about twist! Good luck on the lift.