The 5.3L LS engine in the 1999–2006 GMT800 responds very well to a camshaft upgrade. With the right cam and supporting mods, you can expect significant gains. Here’s what you need to know.
Factory 5.3L Cam Specs:
The stock LS truck cam (varies by year) is designed for low-end torque and fuel economy:
- Lift: ~.460"/.469"
- Duration: ~193/199 @ .050"
- Very mild profile
Performance Cam Options:
Mild Cam (Best for Daily Driver/Towing):
LS1 Tech cam (around 210/218 @ .050") – Noticeable idle quality, more topend power while retaining excellent streetability. No intake or exhaust upgrades required.
Moderate Cam (Street Performance):
LS7 Lifters 16-Pack – When doing a cam swap on the GMT800, replace the lifters at the same time. LS7 lifters are an excellent upgrade that handles higher lifts.
Aggressive Cam (Best Power):
224/224 or 228/228 @ .050" profiles – Maximum topend power, noticeable idle lope. Requires AFM delete (on engines with AFM).
What You’ll Need:
- New camshaft
- Lifters (replace at same time)
- Timing chain and cam phaser (on variable timing engines)
- Valley cover gasket
- Tune (mandatory – the ECM must be calibrated for the new cam)
Power Expectations:
- Mild cam: +30–50 HP at the wheels
- Moderate cam: +50–80 HP at the wheels
- Aggressive cam: +80–100+ HP at the wheels (with supporting mods)
Supporting Mods:
Cold air intake + cat-back exhaust + tune + cam = the recipe for a very capable GMT800 street truck.
Have you done a cam swap on your 5.3 GMT800? Share your results!