Help needed to id strange block!

[Dutchrebuild]

Got to my buddy's shop and checked his out... unfortunately it's on a top shelf...but I did confirm no pad stamps, no casting number, and standard bore 426

 

[pnora]

Got to my buddy's shop and checked his out... unfortunately it's on a top shelf...but I did confirm no pad stamps, no casting number, and standard bore 426

View attachment 1775163

Did you look at the back of the block by the oil sender port for the two part casting number?

 

[Dutchrebuild]

Yup...no casting number