LS oxygen sensors - upstream? Downstream???

[BuddyP]

Went on to Rock Auto to order O2 sensors but see some are listed has "RH upstream" and some LH upstream and RH downstream" and such. I understand that the LS1 camaro had 4, but does it matter which one I get for my LS 1st gen project? I'm of couse only using 2 but a bit confused by the labeling. Just want to be sure I get the proper part.

Thanks!

[daytonayellaz]

Buddy, Get the "upstream" sensors. You had the rear(downstream) sensors shut off in your ECM...correct?

[BlackPearl]

They have a different connector depending on up or down stream. Check your harness and compare to get the correct ones, it should be upstream though considering you don't have all four connectors.