The weight capacity is one factor, but the big thing to consider is the length of the stand. If the engine hangs out beyond the front wheels of the stand, there's not just a possibility, but a definite probability that it will tip over forward with disastrous results. Stovebolt engines are tall and heavy and they can either roll over unexpectedly, or tip the stand over unless you're VERY careful! Some people add an angle iron brace bolted to the front of the engine block to near the floor that will keep it from tipping the stand more than a couple of inches if it gets overbalanced.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!