Probably thousands of people have done this with success, as long as the bolts are tight. Probably has something to do with some engineering calculation that one of our graduate engineer members could detail. That being said I've just never been excited about the idea and use two lift loops that bolt to the cylinder heads with a sling hooked to each. Just my own bias. Aluminum heads haven't seemed to mind (again, as long as the bolts are tight and have sufficient length to maximize the number of threads of contact).