Others can chime in, this is just my research on them.
1) The cup of the new "LS7 design" lifter is .050 deeper
2) The LS7 design is the new "replacement" for all LS platform motors
3) I went to my local O'Reilly's to get LS7 lifters and the Seal Power part number they gave me for a LS lifter is the same part number for L36/67 motor (HT2148) I'm not sure if this is for the 5.7 or 7.0, but knowing you can't get LS1 Lifters from GM anymore, I just assumed Point 2 is correct.
4) *** This comes from my parts store experience *** Box is just that, a box. IIRC there is only one "lifter" manufacturer in the US that gets distributed in many types of boxes. When I worked in a parts store, if we had a vendor change we didn't change parts we changed boxes. We went from some brand (forgot what it was but it was a green box with grey stripe) to Borg Warner and all we got was boxes to swap parts...
Am I off my rocker, I could be... This is just from my research. What did it for me was the deeper cup in the new LS design lifter... My $.02
