weird vibration after headers
 

i know its a long shot but I figured I would ask on here. I just installed bbk lts with the ory and my car is now making this weird real loud vibration noise like at 3k rpms from the rear and if I am slowing down it gets real loud. The y pipe was banging when I first installed them but I adjusted it to where its good now. Any ideas? No I did not do motor mounts but I didnt think they would stop this weird vibration noise.

Headers banging the k member?

you got it right. motor mounts should eliminate that. mounts should go together with long tubes.