Some time back I received a considerable amount of assistance and input regarding grill blocking on my 07 Sierra. I just wanted to say thank you to all who took the time to provide me with your input and ideas. I now have 80% of my grill blocked and it runs well even in 90 degree temps. I am also following the suggestion to carry the basic tools needed to remove the block should the truck start to hotter than normal for whatever reason. While I do not have any empirical data to provide, since I'm still trying to balance my SG, the truck seems to have picked up a little bit of mpg's.
Again, thank you!!