I have a 99 2500 4x4 Gmc with the 6.0. I am wanting to start doing some modding. I am thinking a mild cam, headers, exhaust, injectors and definately some tuning. Eventually i am wanting a turbo. I looked for the markings on my heads but could not find them in the normal spots. I have heard that the 99's have crappy ecm's, is that the case? Any help would be greatly appreciated, i have always had hot rodded diesels and now am moving towards the gas side!

Thanks in advance
Chris

 

The 99-00 6.0L engines had Iron heads W/ 873 Castings. 01- up 6.0L Has aluminum 317 castings. Lots to learn and this is a good site to start.

Here is the heads spec Details

Casting Number 873
Head: 1999-2000 LQ4 6.0 Liter Truck
Material: Cast Iron
Part Number:
12561873
Combustion Chamber Volume: 71.06cc
Compression Ratio: 9.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 317, 035
Head: 2001+ LQ4 and LQ9 6.0 Liter Truck
Material: Aluminimum
Part Number:
12562317 -LQ4
12572317 -LQ9
12572035 -LQ9
Combustion Chamber Volume: 71.06cc
Compression Ratio: 10:1 LQ9 Flat top pistons
Compression Ratio: 9.6:1 LQ4 Dish piston
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches


Copeid over from...
https://www.performancetrucks.net/fo...6&postcount=17

While Mortec.com also has some of this info, they don't have specific details and I have found some of there Info is not accurate....


As far as the ECU goes It was the first year and they did make changes in 01 to better the programing but I would not worry about it. Any competant tuner can reprogram it for you. I would wait to spend the money though until you put the mods on.

 

So the heads r just cast instead of aluminum, pretty much the same except for compression.

Would it be worth it to try and find some 317's?
Also is there any other downfalls to the cast iron besides weight? Should i just find an aluminum engine and swap?

 

i like your truck Chris welcome to the site! personally i'm not too worried about the weight as the truck is so much heavier anyways...

 

Thanks,wastedrubber,

I was not going to modify this truck just going to drive it, but my brother has a 5.3 with some mods and it sounds and runs sweet.

I have a lot to learn been building diesels for years, could build a cummins with my eyes closed but gas is totally different!!

Just trying to learn as much as possible.

I still want to tow lightly with my truck, but want it to sound bada** and run decent.

Any cam suggestions?

 

Its actually believed that the Iron heads are better for less heat soak in the FI community. I wouldn't worry about it. Run what you have.

 

That's kinda what i thought but not for sure!!

 

as for a cam, depends on what your plans are. are you plannin on stayin N/A or do you think you may boost it? I've got an LS6 cam waiting to go on mine as it's proven to be a good turbo cam, but for N/A it wouldn't really have a nice lope if that's what you're going for... it would still be an increase in performance though.

 

for now just stay N\A. In the future, a year or so after i build another garage maybe turbo.
I want a good lope, something that is going to sound good run good and still be daily driveable!