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285 or 295 HP

cowtown_Z71

Full Member
Joined
Mar 12, 2004
Messages
11
Location
Calgary, Alberta
Can anyone confirm that the 5.3 factory HP was increased to 295 beginning 06/03????

How would a person be able to confirm when there engine was built???
 
the 2004 model year 5.3L engine had a higher Hp rating then 2003 model year....

2003 = 285
2004 = 295

It is based on model year truck as far as I know
 
I've seen some pubs. list the 5.3L at 280 hp too, probably varies like mpg or how much our 31 gal tanks hold. ;D
 
GM did some dinking around with the engine to get the extra 10. There are no changes to the engine. The peal HP is likely at different RPM's as well. As I recall the max torque dropped a little to get this. I'll take torque over HP any day with a truck.

I looked a stock dyno results of the two engines and at the rear wheels, over the curve, there really isn't much difference at all.
 
Hey, if you are from cowtown you can always scoot up to Davenport Racing and review the logs (y)
Stock z-71 were getting between 210-220 as I recall. I expect the 2 wheel drive version would do a little better.

If you are from Calgary... what part of town?
 
I remember reading on another chevy forum somewhere (i'll research) that the 03 and 04 5.3's are no different. Both in fact have 295hp althought it's advertised otherwise.

Mud!

Ok, couldn't find it, but asked a friend of mine who initially told me. This is what he said


There was no direct discussion. This is a group opinion.

I know for a fact GM retooled the Vortec 5.3 in '03. This included raising the piston rings to a higher point on the piston. GM made changes to the Fuel MAP when Mass Air-Flow is ignored and only the Manifold Absolute Pressure Sensor is used when Wide Open Throttle. GM also changed to a slightly higher-flowing Catalyst System. In '04 GM went to a returnless Fuel System, but no one I know can determine why this would be a power increase. We do know the '03 and '04 lay down similar Rear Wheel HP numbers when the same gears and overall tire size is used.

Different info gathered from MANY different sites.
 
Great info...Thanks...Pretty much the same then....

Sparky, I'm up in the NW....In Hanson Ranch....Will stop by your shop sometime...

 
cowtown_Z71 said:
Great info...Thanks...Pretty much the same then....

Sparky, I'm up in the NW....In Hanson Ranch....Will stop by your shop sometime...
Just to be clear, I have nothing to do with Davenport. That is just where I went to get a dyno test after many of my mods were done, and who I went to for references when I was having problems with the drop kit.

 
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