I fixed the vibrant on accident... I redid the rear most hanger on my exhaust hoping it would make the drone less intense on the highway, as it had one of these cheap "hangers" welded to the the frame rail. It worked, it was a bit quiter at highways speeds, I could hear the 525LPH walbro at idle, and my 4k vibration was gone. I do still have a mild vibrant between 3500 -3750rpm but that's probably from using poly leaf spring bushings as custom motor mounts.
