Mopar 400 block 8 sleeves

Have you tried Oliver Zinn, The Mopar Shop, in Germany? He might have a block and other parts.
I have not, prices there make restoring a Ferrari interesting option money wise...
I only use them when there is no other option. They have stuff but not for my wallet depth.
They have a 1978 400 block prepped + 500ci stroker kit for 6600$ bored .040" over on their website...