Call me a hillbilly, but a 1” wide polyester ratchet strap will hold close to 4000 pounds of force, wont transfer vibration, is easily installed/ removed, and costs about $8.00.

I’m only guessing here, but I would assume that your engine makes under 500 lb/ft. Using 500 lb/ft as a base number, anything that will hold 500 lbs of force mounted 1 foot from the crankshaft centerline will do the job. Worrying about headbolt shear is a non issue. You could quite literally lift your entire car from one cylinder head with no ill effects(to the engine) with ease.

As far as block damage at the factory mount... It is very common to see the corners of the engine mounting bosses cracked off. This is a poorly designed and machined area from the factory. But it is almost always seen on the passenger side. The engine in my car was mounted by the factory mount bosses( broken pass side when I got it ) and it made over 900 lb/ft of torque. The car weight was 3700 lbs, had a 3.50 rear gear and ran high 8 sec 1/4s. Never had any issue with engine mounting.