I have a 2000 excursion with a 6.8 v10 putting the heads back on it and notice that the intake manifold inlets are not the same. I have been researching for hours and have had no luck as to why or what the difference is. I find one or the other randomly used as the item picture. I have check many different years of this engine and also different vehicles it comes in same result. Could anyone help with what the difference is and which one I need for my engine? I have not checked the engine yet to see if it matches the truck yet. Also do i even need to worry about it? My thoughts are that one definitely has lagers inlets than the other causing an uneven amount of air resulting in unbalanced power banks. Just a thought, as i'm unsure as to how sensitive these engines are.

 

I haven't seen any V-10 heads up close and personal with the intake manifold off to make the comparison so I'm just throwing this out there as a possibility. Are both of those heads the "PI" (Performance Improved) version? Maybe the one with the bigger ports is a PI head and the other is an older non-PI head that was swapped on earlier in it's life.
Look on the exhaust side of the heads just above the ports for this "PI" identification on both heads.

 

That's definitely a non-PI versus PI head. The one with the squarish ports is PI.

The compression will be different. Which is something you do NOT want.

What does the intake look like?

 

I apologize for the depart on the original post.

Has anyone used PI heads with the non PI intake? on the 2.3 4cyl the hot set up used to be oval port head with D port intake. the step helps keep reversion from big cams from making it up the intake and oddly improves flow.

 

What Krewat said one thing to note is that all excursions came with the PI heads. The way to tell is by the heads markings obviously with a PI stamped on the exhaust ports and behind the head.

 

Thanks for the info found the PI marking right where you'll said that it would be. Now all I need to do is get another one to replace the odd ball. Smh

 

I've heard of the non-PI head 4.6L's being able to use a PI intake, but not the other way around. Not sure how the ports match up.

 

4.6 and 5.4 use the same heads, and yes it can be done but you have to use the NPI gasket and use lots of RTV on the water passege gasket, I wouldn't see why it couldn't be done with the 6.8.