I prefer driving my '41 truck with the windows down at highway speed to let the noise out although at the moment I am adding sound deadener.
Try this ,, have a friend tape up the hinges and door gaps with you inside . Drive it and pull off the tape a foot at a time, when you here the noise ,that is where the problem is !!! Then you know where to work...
Mine has a flat windshield, no insulation or deadener of any kind, just the bare metal cab. Full rubber floor mat and seat upholstery about the only things in the cab that aren’t bare metal. Add the glass pack exhaust to the wind noise and bare metal cab noise, well, it’s rather loud at highway speed. Apparently I don’t care. It’s a small cab, so Mrs M is sitting right next to me. I’m a little hard of hearing, especially on the right side, so if something needs to be said, she speaks up. We put 400 miles a week on our DD driving to work and back together. Plenty of time for quiet conversation. When we drive the truck, I like hearing all the racket it makes. To each his own, mine’s just an old beater anyways.
Make up a dish soap solution brush it around gaskets, go inside car and blow compressed air around seal. Have someone out side looking for bubbles.
Good one. To add , you will slow down to appease her ,there by reducing noise.Results= Safer, no speeding ticket, less noise( wife and wind) and no fun behind the wheel.
Beat me to it, Ben! Also, Arizona, Nevada, Montana, Utah, Idaho, South Dakota, and I'm sure I missed one or two. Sent from my SM-G955F using The H.A.M.B. mobile app
Crack a window open about a 1/2" where it's at it's worst. If things lighten up even slightly you'll know what to from there. BTW, still have the side cowl opening for the heat and a cowl vent? That truck likely has no development DNA in it for 70+ MPH. What was the cruising speed stock? Maybe 50 if you're lucky?