I replaced all the rubber mounts in the rear crossmember and engine/transmission mounts on my '63 convertible and don't have any vibration problems at all. The only time I've had a problem like that was right before my '62 diff went out. Joel in Keller, TX (DFW area) '66 Corsa w/air '63 Greenbrier 4spd '63 Greenbrier 8dr 4spd "Bob" '63 900 Convertible 4spd '67 Monza 4spd Posi '62 Monza Wagon PG 15 others