Stock HP in '97 Sierra, 5.7L?

[RacingFan]

I just bought a '97 Sierra 1500, Z71 w/5.7L and am curious what the factory horsepower was for this engine when new? It has a lot of miles, 195K, so I don't expect it to be quite as powerful now but wanted to get an idea on what it used to be.
The engine doesn't smoke when starting nor running so I think it's still pretty tight. Overall the truck runs great, but I'm wondering if there might be anything to do to improve the MPG (I've gotten around 15 so far, not impressive).
Any advice would be appreciated!

 

[Molson02536]

I just bought a '97 Sierra 1500, Z71 w/5.7L and am curious what the factory horsepower was for this engine when new? It has a lot of miles, 195K, so I don't expect it to be quite as powerful now but wanted to get an idea on what it used to be.
The engine doesn't smoke when starting nor running so I think it's still pretty tight. Overall the truck runs great, but I'm wondering if there might be anything to do to improve the MPG (I've gotten around 15 so far, not impressive).
Any advice would be appreciated!

Stock 5.7L Vortec 255 hp V8 was the standard rating for that engine on the Sierra. AS for better gas mileage other then having your PCM re tuned, keep your engine maintained.

Since you have just bought the Sierra and not knowing how the person has maintained it before you. It would be a good thing to give it a Seafoam treatment to clean out any carbon build up in the engine and also run some Marvel Mystery Oil with your engine oil to clean out any carbon and sludge that is restricting and oil passage journals.

http://www.seafoamsales.com/
http://www.marvelmysteryoil.com/
http://gmcowners.com/gmc-forum/showthread.php?t=13770

 

[RacingFan]

Stock 5.7L Vortec 255 hp V8 was the standard rating for that engine on the Sierra. AS for better gas mileage other then having your PCM re tuned, keep your engine maintained.

Since you have just bought the Sierra and not knowing how the person has maintained it before you. It would be a good thing to give it a Seafoam treatment to clean out any carbon build up in the engine and also run some Marvel Mystery Oil with your engine oil to clean out any carbon and sludge that is restricting and oil passage journals.

http://www.seafoamsales.com/
http://www.marvelmysteryoil.com/
http://gmcowners.com/gmc-forum/showthread.php?t=13770

Thanks for the advice, Molson02536, I appreciate it!

 

[RacingFan]

Thanks for the advice, Molson02536. I appreciate it!

 

[RacingFan]

Along those same line of questions, what kind of mileage do most of you get with the 5.7L, with something near 1997?

 

[Sicklajoie]

Along those same line of questions, what kind of mileage do most of you get with the 5.7L, with something near 1997?

I normally got 13-15mpg.

 

[RacingFan]

I normally got 13-15mpg.

I just ran my first full tank of gas and checked the MPG. I got 13.8. Not very impressive, but I guess I can't expect much more for an older vehicle with a 350 engine.

 

[Molson02536]

I just ran my first full tank of gas and checked the MPG. I got 13.8. Not very impressive, but I guess I can't expect much more for an older vehicle with a 350 engine.

Once you have cleaned out the engine as mentioned earlier, see about having your PCM tuned for better performance and economy. I have a HP tuner and tuned my 1996 Jimmy and is now getting almost 23MPG on the highway with an average speed of 72 MPH with the tire combination size.

HP tuner is expensive, so the next best thing would be having your PCM re-tuned by http://www.pcmforless.com/. There great guys and be happy to answer any questions you have and yes you'll get more HP and the crazy thing about it, your also get better gas mileage.