Magnaflow makes a Cat back for your suburban and clams to add another 22 HP and 22 lb-ft of torque.
Magnaflow part #15699 V8 5.7L GAS 5 x 11 x 22 in. Dual Inlet Muffler, 2.5 in./3.5 in. Tubing; 4 in. Tip, SINGLE REAR SIDE EXIT
There are a few things you can do with your 5.7 L vortec to get more out of it and free to do. You can remove the screen from your MAF, just remove the MAF and place it on a bench. Snake a flathead screwdriver through the MAf, not to touch the filament and tap the screwdriver to knock out the screen. Reinstall and your done, this will lessen the air restriction to your throttle body. The throttle body blade it self has a restriction baffle you can remove. Look down the throttle body at WOT and you'll see a half moon baffle that you can remove. Take the two torque screws off that hold the throttle body blade and then open the throttle to WOT and slide the throttle body blade straight up. You may need to clean the throttle body first with throttle body cleaner, you may find the carbon build may keep you from removing the blade easily. Once you have the throttle body blade off, cut off the half moon restriction baffle and grind down any ruff edges left behind and reinstall. You can buy the modified throttle body from E-bay, but they range from $40.00 to $80.00 and there modified just like yours. You can start with these two things since there free and if you are going to get the exhaust, remember to install a cold air intake system. They both go hand in hand, keep us posted and good luck friend.
