I have an 76 auto( which i plan to switch to manual in the next 2 years) so i can only change the muffler to keep some backpressure on the engine. I was wondering how thansa sounds compared to stock at idle, hard accelration, and at cruising speeds. I also have high compression pistons( im not sure if that will change the exhaust sound or not, as i'm fairly new to this). your help is much appreciated