Four Corners Pre-Cast. Pre-cast concrete products, from retaining... Four Corners Precast Concrete Products Four Corners Pre-Cast is a subsidiary of Navajo Engineering, and offers... pre-cast concrete products from septic tanks to retaining walls, storm drains, catch basins and curb drop inlets, New Mexico Highway Department DOT storm sewer inlets. And... irrigation concert products, Redi-Rock retaining walls, median barriers, ranch products, ditch liners, feed bunks, cattle guards, grease traps, cisterns, and parking blocks. We also make concrete pre-made buildings for pump houses, storage and other uses. ...