Guy's i'm just curious if anyone has experienced retarding from their loudmouth, or any type of exh vibration causing the computer to retard timming bya few degrees?

 

not at all.

 

If the exhaust is coming into contact with the chasis, then yes that is a possible source for knock retard. Just swapping out the exhaust though isn't enough by itself. It's the vibrations of the system coming into contact with the car that can trigger the knock sensors. However, other things to keep in mind that are more likely to be the source could be faulty sensors (common on '98 f-bodies), bad gas, bursts of air undetected by the motor (aka burst knock), etc. Check the forums over at LS1Tech and you can read about it all night long...

 

I haven't had that problem myself.