Tax Blocks - mattyschell/nyc-spatial-rolodex GitHub Wiki
The Department of Finance publishes tax blocks on the Property Information Portal. To support the Property Information Portal the Department of Finance publishes a tax block service on the NYCMaps ArcGIS Online organization. The Department of Finance also publishes these blocks in some form on the NYC Open Data Portal.
See Tax-Map for more background.
Tax Lots nest within Tax Blocks.
NYCMaps ArcGIS Online
This is what you want.
Tax block service updated monthly (stable)
Tax block service updated daily