Can anyone let me know where I can find info on changing these mounts?? It would be very much appreciated Thanks Runamuck

What kind of info are you looking for?  I had to replace the mounts themselves along with the captured nuts in the body and the bracket on the frame and the steel reinforcing plate.

I am looking for any and all info I have broken tht head off the #4 mount on the driver side so far. I just would like to know is there a sequence of things I should do and how have others done this job successfully.

You should soak ALL of the mount bolts with penetrating oil first...for several days before attempting to remove them The #4 bolts are accessed(to squirt oil on) from inside the rear of the compartment, in the corners. If the head of the bolt is already broken off, you may be in serious trouble.
You'll need to lift the body up on each side to remove.replace the mounts...some folks have managed with just a 2X4 down the lower body, and jacking up a little, until the mounts will clear. Trouble is on your deal..the bolt is still in there. You'd have to raise the body up at lest 6-8 inches to clear the bolt. That's not gonna be possible without disconnecting a LOT of stuff, including the steering shaft/column.
You may wind up having to use a "sawz-all" to cut the bolt off flush at the top of the mount, with the body jacked up enough to get a gap between the mount, and the body. Then, you may be able to use vise-grips, or more likely a pipe wrench, to screw the bolt out...after soaking it in penetrant for days.

I did mine with the body completely off, it sounds like you are looking to keep the body on?

Hope I'm not too late on this one, but if you only broke the head on your #4 don't panic.  I just did the same on mine a week or so ago.  I also had to cut off the other #4 on the passenger side.  I removed the cage from the inside of the #4 mounts, mine ('77) were just riveted to the body/reinforcement.  Then you can just pull the rest of the bolt up from the inside.  When you put the new one's back in, just use a big washer and a nut, have someone inside hold the nut so it doesn't spin.  Its pretty easy.  My frame brackets on the #4 were both rusted away so I had to cut them off and weld new one's on.  My only problems were with the #4's.  #2 and #3 looked in great shape, rubber bushings could have gone longer, the #1's were ok except the bolts started to rust away to nothing inside the steel sleeve between the bushings.