More info- definitely in the suspension. I pushed in the clutch and shifted into neutral at 60 mph; same vibration.
Will do, but I suspect something else. I had the tires & wheels road-force balanced since then, and they checked out OK. I'm wondering about ball joints and control arm bushings?
I had a tire with a separated belt, it would "shake" at speed, the road force balance didn't change it. But rolling slowly, you could just barely feel some side to side movement. I'd jack it up and spin one tire at a time to verify the tread doesn't deviate from going in a straight line, OR slightly up and down. Also, if it was a front tire hit, take a tape measure and check the toe-in. Cheaper than having it aligned again, normally caster or camber won't make it vibrate.
Hi BB , did you sort this issue ? Rod end or suspension bush ? I take it you have if you are going on a road trip ! Denis .
Front end has been checked by pros, and they say no worn, bent or broken parts; everything is tight. Also had the front wheels/tires dynamically balanced vs. static balanced, which required both inner & outer stick-on weights. Outer weights are not my first choice, but they put them on the area where the Torq Trust spokes meet the rim, not on the face. The tires spun smooth on the balancer, and it's about 95% fixed now. They are also searching for some hub centric rings to fit the Torq Thrusts on the '67 Mustang disc brake rotors. If that doesn't do the trick, I'll just have to live with it. It's not a severe shake, just a minor irritation right in that sweet spot of 50-60 mph where I spend a lot of time.
FIXED! New U joints did the trick. I had found that one side of the front cross had about 1/16” slop. The vibration HAD to be something spinning at a higher rpm than tires, not a tire balance issue. I also stabbed a new tail shaft seal in there too, since the old one had a minor leak, maybe from the sloppy U joint? I found a couple part numbers on the yoke and the driveshaft, and some factory paint markings on there too:
