Kendall, 76, CircleK, Conoco, and Phillips are all brand names of ConocoPhillips Corp. I've looked at some data sheets for Kendall and 76 oils, and they look the same to me. With the new formulations for ILSAC GF-4 & API SM expect more identical oils within brand families unless there is a desire for a lower quality/lower price product like Wolf's Head vs. Formula Shell, or a higher quality/higher priced product like Valvoline Premium Blue (conventional) 15W-40 vs. Valvoline HD 15W-40.
I'd expect Kendall to be idential to 76, Conoco, and Phillips Trop-Artic unless the data sheets show a clear difference. 76 and Kendall European Formual synthetic 5W-40 are both said to be very good.
Ken