[Power Surge]

NOS blocks come up pretty often on ebay. They usually sell in the 5k range.

Keep in mind that most of them are "service" blocks (over the counter replacement blocks, with the ribs on the side and usually no date coding). Also keep in mind that many original blocks have core shift issues, so you should sonic check the block after (or before) buying it. You might wind up sleeving an NOS block.

I would strongly suggest getting a Pond iron or aluminum block instead. The same money (about 5k) and a brand new block that has the proper shape and date coding to an original block. Paint it black and it'll look just like that 40 year old NOS block.