Vibration-motor mounts or CV joints?

I am having vibration problems with my 88 lxi w/automatic and 68,000 miles. Soon after purchasing it last year, it developed a vibration when accelerating above 25 mph. After scouring you site, I decided that it was probably the driver side inner cv joint so I replaced the half shaft (along with the passenger side while I had the car up). Almost immediately, the outer joint on the drivers side started clunking though it didn't seem to vibrate. I drove it that way for a couple of months until the clunking got too bad when I replaced it again a couple of weeks ago. Now I’m getting a similar vibration that I had with the original one but with no clunking.

The counter person at Checker told me that I must have a bad motor mount and that is what is causing the vibration and extreme wear of the cv joints. I did a visual inspection and found that the transmission mount bracket was broken which I replaced yesterday. The car still vibrates!

My first question is, what is the normal amount of engine movement? While revving the engine against the brakes while in gear, the front mount deforms enough to allow the front of the motor to lift over a ½ inch. Is this amount of play normal for this type of mount? Also, when the engine is not running, the torque bar (dog bone) has a lot of side to side play on the engine end . How tight is that bushing supposed to be?

The other option is that the motor mounts are fine and I have just been unlucky in getting two defective rebuilt half shafts from Checker/Kragen. Has anyone else had problems with Checkers half shafts?

I would appreciate any ideas or opinions on this problem. Thanks!

It's hard to imagine how the mounts could be broken with only 68,000 miles on the car. Your symptoms do sound like broken mounts though. I have heard of people having cv joint problems like your due to bad cv joints from the parts store and had to replace them several times before getting a good one. My bet is on the engine mounts being bad.

they rot. You probably have a shredded mount somewhere. When i did my accord, my front mount, timing belt side mount, and dogbone were shredded to pieces. My bottom tranny mount i just replaced because it shredded too

After you replace a worn out engine mount you should torque all of the mounts down in a specific way so the engine seats correctly and so your CV joints don't endure undue stress. THis process is outlined, explained, and pictured in the FREE ONLINE Honda Manual which is downloadable in the sticky in the Tech Section. I would try this route first.
The dogbone mount on the firewall is usually loose side to side and I replaced mine a few years ago and it didn't help with engine movement at all. A 1/2in, in gear, doesn't sound like too terribly much, but possibly a bit too much. The front and rear mounts are easy to tell whether they are shot, Jack the the engine up from the oil pan, loosen them from the frame rails and if you can make them pivot easily with just your had they are shot. These two are filled with oil and when they spring a leak they just sit there and do nothing except let the engine move all around. Usually the tranny mount makes the biggest difference when replacing them since it does the most at limiting the engine's movement (the bigger the piece of rubber is, the less the engine moves inside the mount). The driver's side mount would most be susceptible to dry-rot since it is just rubber and no oil and it suspends itself inside a metal housing it is attached to. Jack up the engine a bit and see if you can get the engine's weight off the side mount a bit. If you can and you can move the part where the engine attaches inside this mount more than a 1/2" in any direction this mount is probably shot. I don't know how hard this one is to replace since it is actually the only one I didn't have out at one point or another. It will probably be a little difficult b/c just to torque this mount down when I replaced some of my mounts I had some trouble getting to the nuts and bolts.

on my 89LXi is dry and shed. Should I replace it immediately or it can wait?
There is no vibration at the engine. To replace it, unscrew the two bolts on the bracket. Is it correct?
Thanks.