So that you can get an overall understand of what exactly the 6.2 and 6.5 liter diesels are, how they ever came into being by Detroit diesel; and how important they are to us and that we equip our Suburban with these engines (the 6.5 by the time we buy our Suburban), here is an article about these engines.

6.2L diesel specs, history, and information. The 6.2 diesel was manufactured by Detroit Diesel, a division of General Motors during the time period and used in Chevrolet/GMC trucks from 1982 until 1993.

Source: 6.2L GM/Detroit Diesel Specs & Information