Should be same metric thread as bottom bolts. Not digging part bin and maybe finding them.
If bottom nuts won't fit, is likely thread damages you can't see well...
or...
Some nuts for engine/trans mounts are "lock nuts" and may only fit one way to start w/o tools. Once started, will need tools to tighten or remove for rest of bolt/stud length.
If new, bolts may have paint hiding iffy thread or make them too big to start the nuts.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
