[mongocanfly]

That's interesting that your 6.0 with all those mods only turned 328...
Mine stock did 344hp and 399tq...I know I'm way lower in elevation than you, but I wouldnt have thought it would be that much of a dropoff..
But it was practically the same with manis as it was with headers on mine
But I will say..I drove mine over the vail pass a couple months ago..pulling a empty trailer, there were places i could barely maintain 55...
coming back loaded...well we dont want to talk about that..haha
I know hp mods work better with headers ...sounds like it's time to bust out the checkbook..
I'd be real curious to know your results with only a swap to headers..
Your LQ4 should have had about 322hp bone stock
My LQ9 had 344 bone stock..so you'll notice I gained nothing with the headers