[Jack21]

Anticipating just this kind of problem with OEM Ford rubber motor mounts, used Energy Suspension polyurethane motor and trans mounts. Summit has them.

Poly mounts soak up high end engine vibrations, but the motor doesn't move around at all. Instead of engine rocking, whole car rocks at idle. Sidepipes don't move around either.

Nearly 11,000 miles on car now and no problems.

E.S. Poly mounts are only made for late (83 - up) Mustangs. Uses single 14mm through bolt, and locating tab. Classic Roadsters now uses late Mustang frame mounts that use these. Other brands may need fabrication of motor mount-to-frame mount to use the E.S. late Mustang poly motor mounts. But they solve all the problems listed above if you have a 302, or 351W block.