Do you have any kind of jack? Maybe some tie down straps? If you have any kind of hydraulic roller jack (if you don't, you can usually pick a small one up for cheap), you can just put a block of wood on the top and use that. A bottle jack wouldn't be stable enough. If you had some tie down straps you could wrap them around the engine and up to the frame, or maybe a 2x4 over the frame, and let it down a little at a time.
Of course, the frame itself is pretty light. If you're swapping the frame out, maybe the way to think of it is to lift the frame off the engine instead. You could put some blocks under the motor to hold it securely, take the suspension off and lift the frame away.