Does anyone here know of a source from which 1990 Census Block polygons can be downloaded? For Illinois, specifically, if not for the entire country? The Census Bureau has "no plans to create Block level boundary files", and I know that NHGIS doesn't have the block-level data. I searched the old questions here and found nothing.
Get Illinois TIGER 1999 in TIGER/Line format (by county) from:
Use GDAL/OGR to extract all polygons. Those should be the blocks. GDAL/OGR comes with a Python script called tigerpoly.py that will do this for you.