Im getting ready to go get my LS1 conversion smoged. I failed last time due to high CO . I did not know what tune was done to the PCM when i got the engine. I put it back to stock after i failed smog. The only mod that i did was just do a 3inch exhaust system from the cats back. Single. I have all the smog stuff. Ive been stressing over this all month . I took off TORQUE MANAGEMENTand messed with the tranny shift points and TCC stuff. set the idle a little higher than stock. thats about it. Please let me know what you think . Im running 87 gas. Thanks once again