[mustangII460]

Sorry for the grammer lession. But separate your questions into different sentences. Its nearly imposible to read that.

302/351w/351c use the same motor mounts.

69 Mustang/Cougar mounts are the same.

Take new mounts to another parts store and compare them. Or online picture.

Is the tranny bolted up?

Have the tranny mount on lifting the the motor forward?

I suspect wrong mounts if your sure you didn't mess up assembly.