been trying to figure out the easy way to change these on my 93 d150.
i come up with useing a 10ft 4x4 across the front of the truck,jack truck up chain to the engine around the 4x4,support the ends of the 4x4 with 2 tables,then lower the truck enough to get them out and the new ones in.
anyone have a better idea?? ideas helpfull thank you

 

I have used an engine hoist before or a floor jack with a length of 2x2 under the engine to change mounts. Your way should work if the tables are sturdy enough. Just keep an eye on the distributer to fire wall clearance and the top of the bell housing to tunnel clearance as you lower the truck body.

 

I removed both nuts to the top of the mounts and loosened the trans mount to have some play. Then I did one side at a time by jacking up one side with a 2X4 under the oil pan rail and removed the engine support bracket. I left both nuts off till the other side was in place. Just keep an eye on the trans tunnel and may need to unclip the trans cooler lines just in case.

Have fun.