helloo im new here and just bought a 1997 gmc 6.5 was wonderin what all i could do to it to create more power any good ideas? thanks:

 

You aren't going to like to hear this, but the 6.2 and the 6.5 engines are not performance engines, they were built for economy. They do not do well with performance mods. If you want your engine to last leave it alone and be sure to check the harmonic balancer often. These engines are externally balanced and when the rubber between the harmonic balancer starts to deteriorate it can't do its job as well and the crank will snap in half. However, if you choose to turn up the power first off get an EGT gauge and a boost gauge. These indirect injected engines do not tolerate smoke like the direct injected engines can so be sure to keep your EGTs under control or you will have a major melt down. Don't try to push too much boost, how high you want to go is up to you but the more boost you push the more likely your engine will blow up, I don't think I would try more than maybe 12 PSI, like I say do it at your own risk. These engines are not powerhouses like a cummins but keep them stock, treat them nice, and keep an eye on that harmonic balancer and you should get some good miles out of that engine.
One more thing, your injection pump is electronically controlled so if the PMD has not already been relocated you will want to do that or have the kit on hand for when it goes out. Do a search on the PMD if you are not familiar with it.
Have fun!

 

I'm spinning 271 hp and 440lb/ft at the rear wheels from my 98 K2500.

There's some power in the old design, but it is not cheap to get it out of them.

If I had it to do over, I would have stepped right past the 6.5 and bought a 6.6

 

Thats the key phrase "not cheap to get out of them".

 

What Diesel is cheap to get power out of My 1993 K2500 is capable of doing all that I need to do here recently I had a 27' goose neck on it along with about 300 square bales of hay no problems ran with a empty trailer up a and back on the highway at speed no trouble at all I love my 6.5but I do want a 6.6