Maybe it's just me but I'd just yank the engine and get er out of the way then yank the K-member. Nothing worse than working on the car and having the engine fall on you. It'd ruin your whole day.
When I was installing the tranny on my fish, I ran a ratchet strap between the frame members, running under the oil pan...used a 2x12 there to distribute the load......held the motor up just fine. So I would think that if you did the same thing it would work, provided you had the tranny end mount installed....you are just holding up one end of the motor that way.