CHEAPest way to convert rear axle bolt pattern to big bolt pattern???

Thats why i suggested the cnc machined billet ones made by ballistic fabrication. Not trying to be pushy on them just suggesting becuse you said youve only seen thr cast version which i myself would be leery of to. But they run their spacers on high tourqe rock crawlers and desert race trucks so i wouldnt worry one bit about their quality