Other than the obvious (iron/aluminum) how much difference is there between the 99-00 iron heads and the 01 & up aluminum units? Would the aluminun heads be a direct bolt-on affair for my 99' 6.0? Or is it even worth doing?
Thanks

 

They are exactly the same. The only thing you will gain is 55 less lbs up front.

 

^^^^Ditto^^^^

 

Thanks. I guess the aluminum units may be a little easier to work with as far as porting goes.

 

I have the cast iron heads on my 2000 Yukon XL K2500. I was considering the aluminum heads (which I have done a lot of research on and they are virtually identical to the aluminum and are completely interchangable). Anyway, I am mostly interested in improving torque and a couple of CNC head specialists told me that the cast iron heads are actually better for building torque because they do not disipate the heat as quickly. The head retention is good for torque. Whereas the aluminum heads are better at building high rpm HP because the heat transfer is improved and the compression can be raised a little without detonation. Also, aluminum can be CNC ported allowing better and more consistent flow for high velocity gases at higher RPM's. I'm sticking with cast iron. I've installed a bigger cam and springs and have a hypertech III which I am very pleased with. I run 87 Octane and have set my upshifts at 5700 with an RPM limit of 6000. Great combination.

 

Hmmmm, I'm inclined to disagree. The 01+ models are styles very similar to the LS6 head, which has a better chamber and runner design. Compared to a standard LS1 head, the LS6 heads flow quite a bit more. I'd thinkthe 00- heads would be similar to the LS1 and the 01- would be like the LS6. If thats so, then you'd make more power, have less head with aluminum, and drop weight.

I'd go with the 01+ alum head without thinking twice.

 

99-04 6.0 heads are EXACTLY the same according to the GM techs that I have questioned and the research that I have done...ALL the LQ4/LQ9 heads both cast iron and aluminum are very similar to the LS6 heads in both port and chamber shape

as far as I have been able to determine the ONLY difference is the weight...you can save ~60 lbs by going to the aluminum heads...thats it

 

Time for some investigative reporting.

 

Torque is what I'm after...especially below 3k rpm. I am looking at cams and was wondering what you went with and some other specifics on your setup (exhaust, gearing, etc...).

 

FS mint condition cast 2K 6.0 cast heads complete less than 500 miles $100+ shipping.