ID mystery spacer ???

Pic 1
Mystery spacer, phenolic 1 inch thick

Pic 2
Factory Thermoquad phenolic on top of mystery spacer

Pic 3
Offenhauser 2 inch spread bore spacer
On top of mystery spacer

Damn, no fit

Problem: mystery spacer have to enlarge secondary holes
I really want to use mystery spacer, this one looks like it has good high temp blocking capabilities
Ia am curious about what was the application for it, maybe Quadrajet ? Did Ford do a spread bore ?