Although you can probably reach more especially if you can find someone who needs this casting and date, there's one on eBay right now....who knows what it's really like but has a BIN of only $125....here's the link below. .
Good luck w/ the block sale, sounds like you've a nice buncha' cars....especially that L78 rag! .
~ Pete
http://cgi.ebay.com/ebaymotors/PRICE-SLA...sspagenameZWDVW