Answer to my own query on air strainer/intake filter for a cross-compound air compressor.
Found that a NAPA 2634 or WIX 42634 will be a close fit. Subs are 6 hole mounts, so need to be redrilled to match the original 4 stud cover mount. Paper element, in perf metal cannister, similar to original WABCO/NYAB style strainers.