Harbor Freight sells a U-shaped base engine stand - probably 1250 Lbs, which is way more than you need. Don't get the "one leg" engine stand.

The bolts are 3/8-16 (coarse thread) and should thread into the block at least 1/2 inch. Grade 8 are fine, but 5 is enough. Home Depot bolts are Grade 2 and will work fine as well, just don't over-torque them.