Well, I was just wondering? When I purchased mine I didn't know any of the differences between the two. But, after i purchased the truck I found LS1.com then FSC.com, then LS1tech.com, then here, and most of the sites dog the 4.8 hard. I like it, don't know any different I suppose. But I aspire to have a 5.7L LS1 someday. But in the mean time I am going to get the most out of my 4.8 that I can. Hopeing Allen can help with his tuning as soon as I save of some bucks.