Detroit Diesel GM 71 Series Engine 3-71 4-71 6-71 Service & Maintenance Manual. PLEASE READ DESCRIPTION THOROUGHLY BEFORE PURCHASING. NOT SEPARATING THE LOT PLEASE DONT ASK. Vintage lot of Detroit diesel Gm maintenance manuals. These manuals years range from the 50s to the late 60s. Some very rare print manuals for any collector or mechanic. […]