Also might waht to check out fullsizechevy.com, dieselbombers.com.
you dont say the year of your truck but if it is older than a 2007 the CP3 injection pump on those engines was built to run the old Non ULSD. the new stuff is no slick enough and it will eventually cause your IP to fail. What i ran in my dodge was just plain old 2 stroke premix oil. 1 quart to 32 gallons gave about a 128 ratio, just slick enough to help, but not so oily it will make you smoke (more).
As a nice little bonus it usualy gives people about a .5-1mpg boost. DO NOT RUN IT IF YOU HAVE A DPF. if you have a DPF your truck is built for ULSD anyway.
best of luck with the truck, oh one last thing: Chevy did not install lift pumps in the tank, look into an airdog 150, your injection pump will thank you.