5.3L Dyno Results

[Crack Monkey]

First, an introduction. I'm Alistair. I bought a 1999 GMC Sierra a month ago. It's a 5.3L 4x4.

 

This past weekend, I decided to put it on the dyno. The truck is stock and has 55,000 miles.

 

It put down 200hp with a pretty smooth power band. No big dips or other weird results. The shop was humid, but not overly hot (65 degrees or so).

 

My only gripe is a friends '01 5.3L put down 230hp. We both have 3.73 rear ends. Does anybody know what GM changed between 99 and 00/01 to account for the power difference? From what I've seen, 200hp is pretty standard for the '99.

 

Alistair

[Y2K Silverado]

1999 5.3L's were rated at 270 hp and 315 tq, in 2000 they got the 6.0L cam and power went up to 285 hp and 325 tq.

Jim