I have the 1ton Harbor Freight Engine Stand, there is no problem with the strength of it, I have a 5.9L Cummins sitting on mine no problem.
Of note however, when I bought mine, the head upright supports are too short, or the hole is drilled too high, however you want to look at it. The ones in the store were the same way. I simply drilled a new hole for the supports lower, then put a bolt through the previous hole to prevent any weakening.
Naturally, it does interfere big time with the legs on an engine hoist, so just beware.
Zach