Please explain your grade 5 bolts that failed and where they were used and their size. Not just a blow-off story. They don't fail on any of our uses on our trucks.
I was rebuilding a 292 from an 84 GMC. It was attached to the stand with 4 grade 5 bolts into the bellhousing holes. I mounted it and everything seemed fine until I went to pull the dampener. I put a bar on the puller to break it loose and head a ping.
The dampener still appeared tight, so I leaned into it again and the whole thing twisted to the side and the engine stand fell over barely missing my foot.
The first ping was one of the 4 bolts holding it to the stand starting to give up and when I pushed it again there was enough force to finish snapping that bolt and the rebound overcentered the stand and dumped it.
That story is also a good reminder of the suggestion above to support the front of the engine because it it long/heavy enough that it puts more force on the stand than you think.
