Still working on this sucker. I've been focusing on drivability at 80mph in the summer. Love the traditional look of these new Toyo AT3s.
I installed Noico 80 butyl sound deadener and overlayed that with acoustic foam sound absorber in the door panels. I sprayed Boom Mat spray in the fender wells and underneath the lower panels. I also filled the space between the interior rear vinyl/particle board panels and sheet metal with Van Insulknop wool insulation. The floors were already covered in mass loaded vinyl. All together, this has made a substantial improvement in the sound profile at speed. Also, really working on the side vent glass rubber to ensure a good seal is important.
From there I needed to work on the TH350 transmission shifts. It has shifted way early on both the 1-2 and 2-3 shifts since going to 35" tires in 2014. So, out with the governor.
Using one of those weight and spring
kits, I only needed a single weight and spring to get my shifts to the right RPMs.
I also wasn't super happy that the guys that originally installed my 12 bolt diff cover overtightened the drain plugs. I was fed up with it, so I just replaced the whole thing with an anodized cover and installed a LubeLocker gasket to boot.
Here's some good ole fashioned overkill. How do you kill exhaust sound when you're cruising at 3,200rpms down the highway?
I used RockAuto and a tape measure to figure out the largest mufflers with 2.5" openings I could fit in the space. These two stainless units come out of an early 2000s 4.6L Expedition. Then engine doesn't roar at speed anymore.