It matters not to me, I just suggested you read manual. I will say this, I manufacture Bio-Diesel, and the properties of it are not the same as the current diesel yu buy made from crude. Depending on the % mix it will cause your diesel to run hotter temps. You can NOT burn 100% with out a doubt.

Just something to think about. I understand that GM will say anything, but the truck was designed as is for many reasons. I just feel that before making a l;ot of changes you do lots of research. $6,000 is a lot to pay for a new engine.