What kind of documentation for used engine would satisfy you?

Just sold my spare “core” W8 mill for 6k. I bought it “as is” years ago with 11 dyno sheets 730-745hp. I’d never heard it run, but for the parts alone I picked it up as a potential back up plan. About all I did was pull the valve covers and timing cover to scope things. Never really advertised it, but mentioned it a few times on forums and FB. I dropped it off in Nebraska back in September and it will end up in a dirt late model which is cool.