I think the gm goodwrench stuff is mobil, at least from what i have heard, the ac delco brand is bought from a local ac delco distributor here in town.
Thanks guys, ya i dont use ac delco filters for my truck, they suck, plastic cage and all, that and when ever i use them i get some strange oil pressure readings. i just use microgaurd wix or napa brand, which two of those are the same filter, just depends on who has the better price at the time.