I went on youtube and looked up exhaust 4.8 silverado after seeing a truck at a carshow that sounded nice. The kid that was driving it didn't know anything he bought the truck that way. So being on youtube hearing exhaust systems other videos showed exhaust with cam upgrades. Now they say with the Gen3 motors that they are basically a LS1 platform that the LS1-7 cams will fit into the 4.8 . I've built engines before, but not the new school type. Now would I have to manipulate the ECM so the sensors won't go crazy, and will it hurt the block in the long run. Any kind of tips or ideas would help. I already have shorty headers for it and still shopping for the right mufflers.

 

Shorty headers won't do much for performance on the LS motors (well as much as they would on an old carb'ed 350), but the truck will sound 100 times better. Don't replace the Cats, they are about as high flow as you can get. Don't go crazy on pipe diameter either. Too big will dog the truck at low RPMs. These engines breathe well enough already on the exhaust side so you don't have to go crazy.

Now if you want some serious power get a ZO6 cam for your truck. Yes you will have to tune for the different valve timing and durations. Some manufactures offer a handheld but a custom tune will make the best of the cam. I dyno tune will get her running perfect.

 

I agree! That cam will open her up a lot especially on the top end. But you also need to get some stronger valve springs to prevent valve floating. I put a stock cam out of a 2000 T/A in my 5.3 and made a big difference. It even lopes a little too. I am also on the threshold of gettin stronger springs. The stock springs are good for .500 lift. Im sure the Z06 cam has more lift. But the cam I installed is right at a .497 lift. Now my bottom end torque is lacking a lot. So I will put a 2800-3200 stall converter to fix that. I was gonna go 4.10 gears but with the converter and stock gears I can keep my good gas mileage. Check this guy out. He put a cam and stall converter...

 

Here's a 4.8 07 silverado with a cam and stall....