Motor mount to stand bolts

[mindhive]

I got my truck disassembled and can't find the original bolts that go through the engine stand into the mount. I read here somewhere they are 7/16-14 so I bought a couple, but when I put it in it got really tight. I figured it was supposed to be tight to lock the bolt in but I ended up ripping out the nut from the rubber in my brand new mount. 3/8 bolts are swimming in the hole in my other new mount but I can't even get the 7/8 bolt started. Any help would be appreciated.

Tim