Here's what I did. I made a"U" shaped wood assembly out of 2 X 6 material. I cut the two pieces of 2 X 6 the proper length to go on end under each side of the pan rail. I allowed it to stick about an inch below the pan where I was going to push it up, in front of the axle. I cut a third piece of 2 X 6 to span across under the two end pieces sticking up. I assembled this "U" shaped piece and set it on the jack pad in the center. I loosened all bolts on the front mount, both the mount bolts and the engine bolts. I jacked the engine up slowly checking each time I applied some lift to the jack until I could remove the bolts. After the bolts were out, the mount slid out. I reassembled the same way. I didn't loosend the rear mounts to do this, but that might have helped. I might have been lucky, but it worked great and took about an hour. On reassembly, I also managed to get the metal protector in on top of the mount. Be sure to keep an eye on the upper radiator hose during this exercise. Mine flexed enough, but that could be an issue depending on how your hose meets the radiator.
I did the rear mounts the same way, only I atttemped one side at a time. Using the pan rail to raise the engine is the key. I will tell you, the rears took an afternoon to do - a little more time consuming than the front one. On the rears, be sure to loosen the exhaust pipe or exhaust pipes if you are running headers or a split manifold. The pipes can "float" around a little better while you are raising the engine if they are loose. After you finish, be sure not to forget to tighten them up.
Replacing totally stopped clutch chatter. My old mounts were in terrible shape. I figure they were the 70 year old originals!
Joe
