Re: Vibration @ 60mph
I haven't messed with this much, but today I took the wheels/tires somewhere else to balance. They complained about the one tire a bit but said they were able to get it zeroed out. They used less than 2oz of weight to do it.
When I got home, I jacked the car up by the differential and put it in 5th and got it up to 60mph. I could feel the vibration. I took off the supposedly problematic wheel and tried again. I could still feel it. I took off the other wheel, and no change. So, this is not a wheel/tire problem.
I called the guy who built the driveshaft asking if I could take it to him and have him check it, and he agreed. However, he insisted I was barking up the wrong tree because if it was out, he'd have seen it when he built it. I see the logic. I'm going to bring it to him, but likely in vain.
All this leaves, in my mind, is driveshaft angles (which I've been very diligent about from the start as I've had these problems before) or something with the rear end (which is brand new) or possibly even the rear brakes. I got no other ideas. I'm so frustrated I'm just sick to my stomach about it.
1968 Chevelle 2-door coupe restomod... 496ci BBC, Holley 950, T-56 Magnum, Dana S60, and an idle that shakes the ground.