Left Exhaust Manifold on Fifth Generation LML's ?

[cowboywildbill]

Maybe one of our Dealer Tech's or J.K. or somebody out there might know the answer to this.If you remember the left side exhaust manifolds had the dimmple/restriction cast into them to clear the steering shafts in the early K series trucks ? This is when they were developing and testing the D/max in the 1999-2000 truck bodies ? Prior to production and placement into the new 2001 bodies of which they were designed to go in. Any way I know my 07 still had the original left side restricted manifold in it. they just never changed the casting and produced the same part even though the clearence wasn't an issue in the new body style. As most of you know there is an aftermarket manifold available that doesn't have the restriction in it. I was wondering if anyone know's if the new LML engine finally got a new unresticted manifold, or do they still run the same one's as previous years? Thanks.

[More Power]

Here's a GM clip showing the left side LML exhaust manifold. Other pics of the manifold show a heat shield, but otherwise the same general shape. I don't know whether this manifold will bolt onto an earlier engine... I'm guessing maybe... :)

http://www.thedieselpageforums.com/photopost/data/500/LML-Exhaust.jpg

[cowboywildbill]

Thanks More Power, do you think the restriction was that big of a problem?
I know on our 02 GMC I had EGT probes in both sides and the left side would heat up quicker run a little hotter and cool down slower getting in and out of the throttle while towing. Wonder if no restriction makes much difference with economy and power? Thanks

[moss6]

Aftermarket folks sure seem to think so. Look at the price.

[cowboywildbill]

Hi Moss, I wonder if anyone has done a dyno or egt before and after with the old style and the aftermarket manifold? With a restriction on one side it just seems like the left and right side of the engine would be out of balance as far as breathing and hp output goes. Although I'm sure there are differences with the length of pipes and turbo connections that would alter flow also, but a restriction right at the head seems like it would be more problematic.?

[moss6]

Kinda like equal tube length headers, don't know if it really makes much difference; but cool looking.