Lifting engine for installation

crackedback said
What's the tensile strength of a 5/16 grade 2 bolt. It's 3900 pounds. Grade 5, 6300; Grade 8, 7850

Even in shear, there is more than enough to hold an engine.

If people are dropping engines using one of the plates they did something wrong, somewhere, bad threads in intake, etc.

Yes you are right but remember those test loads are with a nut on the bolt. Not threaded into aluminum or questionable hardness. A 5/16 bolt is only as strong as the metal it is threaded to. Not to mention unless you are using mill spec, MS or NAS hardware you really have no idea how strong that "grade 8" made in India or china TSC bolt really is. Just more of a chance than I am willing to take with my investment.