Slim pickin's out there.
But now that the supply is low, folks are cashing in and who can blame them...
This one sold yesterday (not mine)
https://www.ebay.com/itm/NEW-MOPAR-PERFORMANCE-DIRECT-CONNECTION-426-HEMI-ENGINE-BLOCK-NEW-/264270095224?item=264270095224&vxp=mtr&ViewItem=&nma=true&si=tyiY2mkj9Xkdqmp63dg2bCg8VL0%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
Damn. But, if it's what you "have to" have, then I guess that's the going price. Which brings us back to the OP's question about this conversion.
