Does anybody know what was changed on the 5.3 to up the hp rating from 99 to newer year models? 1999 was 270hp where 2000 was 285hp. Was it just tuning that was changed? I asked a parts person at a local chevy dealership, and he didn't know. Is it possible that they just underrated the 99?

 

I think it is tuning and maybe a cam.

 

didnt they upgrade the rod bolts in 2000?

 

Cam, injectors (from 19 to 24lb), and tune off the top of my head...Zed

 

Trust me the 99's were not overated. They used the 6.0 cam in the 5.3 and 4.8 for 2000 along with tuning tweaks. That's it.

 

Plus the injectors like storm5.3 said, except I think the 99's were 21.7 lbs while 02 and up are 24's.

 

Yes you are almost 100% correct. The 2000's started with same injector across the line. I failed to mention those because he asked about where the increased power came from. The 99's typically dynoed around 210 horsepower at the wheels. We have come a long way.

 

mmy 99 beats an 05 5.3 by one car length and i have 115k miles on it they have like 32k

 

What are the specs and mods on your truck? Ext-cab, regular-cab,etc.......? How about the 05 truck? If ya'll both are all stock I find that hard to belive!!!!

 

I've got a 99 RCSB with a 5.3, and raced a stock 2001 just like mine. I beat him half a truck length. All I had was a FIPK, TB spacer, and a flowmaster.