Thanks...Jim at Kilpatrick's engine and trans (a mopar specialist) was pretty sure they'd fit since he's installed about a 1000 of 'em on cars (but never a D-series). They did great work; I was told it was a pretty straight forward installation too, far easier than most cars

My best personal installation was leak-free for ~ 3 months. After that, the "tick-tick-tick" header leaks returned inforce . This was with 1/4 inch thick flange hedman hedder's. I thought I could beat them .....

Better yet, for my application, it feels like more power too! I felt that the 408, 2.08/1.65 valved cnc'd eddy heads/roller cammed engine wanted more than basic 1 5/8th headers. While I wouldn't have minded 1/34 all the way, I actually think how mine is configured, it may make broader power w/ the stepped 1 5/8th-1 3/4 step than a basic 1 3/4 header, even if it gives up a little peak power.

Truth be told it could also be because of the new MSD ignition (replacing a mismatched stock unit that had a good ignition curve none-the-less) and the increased traction from the sure-grip diff too...all put together, this truck feels like a different animal. Will still spin them easily at 40mph