SS block for sale (1970)

I saw this block on ebay 512 casting looks like a 1970 block for a 4 speed, but cant figure on Camaro, chevelle or monte, 4 bolt main caps
what you think?? heres a link

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7954810844&rd=1&sspagename=STRK%3AMEWA%3AIT

I think its a 454 450hp block.
It's a CRV not a CRN. 4spd manual It has no other numbers after the CRV code which means it could fit whatever you want it to fit. It was a replacement motor.
CRN code came out in 1972 270hp automatic
Tonowanda plant casting is Aug 2 1969
Install date of Sept 3 1969
!970 models were in production at that time.