I replaced the stock muffler on my 94 Z28 with a Hooker Aerochamber and it is just as quiet with this as it was with the stock muffler. What do I need to get it to sound better. I dont want it to sound like a farm truck I just want a little noise/rumble.

 

If you are looking for improved performance, and not simply louder sound, you need to consider a full 3" "catback" system. This would bolt to the outlet of your cat converter, run a full 3" mandrel-bent intermediate pipe to the rear axle, and up and over it, and then a cross-flow muffler with dual outlets. The stock intermediate pipe is only 2-3/4" and seems to hinder performance. I'm pretty sure I got 10-15HP out of my Borla adjustable catback. Couple that with a quality cold air intake (CAI) and you have 25HP and a 3/10-second reduction in your 1/4-mile performance.

Just changing the muffler will not result in much in the way of HP gains.

 

Just swapped the stock cat back on my 2000 Z28m6 with the Magnaflow system got it on ebay for less than $300 sounds real nice twice as loud as the stock but not as loud as the Flowmasters. Noticed a difference in power and added a SLP lid K&N filter and smooth bellows without a tune and over 130,000 miles it runs great and gets over 27mpg hwy and 22 city plus its all stainless and has nice polished 4 inch pipes. Sounds way better than my neighbors Mustang LOL