I thought it was pretty intresting that GM is now using a 4/7 cam lobe swap on the firing order, performance cam manufactures like Lunati, Iskenderian etc. have been selling cams like that for years. Guess all those millions of dollars in research wasent for nothing after all! Probably makes 20" or more vaccum too. FYI, .549 lift .300 dur. and 108 lobe sep. = about 7" vaccum.