Hey I had an lt1 z28 with like 175000 miles come into our shop and when you had the hood up when it was running just looking at the engine it was quiet and looked like you could balance a penny on its edge on top of the intake smooth idle. My car has almost 90k miles and shakes a decent bit, maybe a slight miss but still, and makes all kinds of noise. Now do headers make underhood noise louder since it may not absorb all the sound like a big thick cast iron manifold does? I use the best oil I know of in my motor and the other guy was putting in **** pennzoil 10w30 and his valvecovers had NO ticking coming from them at all and mine have some but I cant tell if its loud *** injectors or valvetrain noise its just ...noise and shakey.... how can I get my car to run dead smooth like that and shut the **** up? Obvisously if its the thinner walled headers making some noise I wont change that. Also are missfires the only thing that makes a motor shake if the motor itself is in internally perfect condition?

 

TTT - Curious about this too