The simplest, cheapest, and MOST EFFECTIVE cure for preventing a broken engine mount (driver's side only) is two strong bolts through the mount. I did it to my existing mount, and the mod itself takes 15 minutes. Getting it out and back in is another story, but that's the case no matter what product you use.
One bolt will work for 99% of our applications, but because I have a warmed 440TNT and an irreplaceable fiberglass Hurst hood that hates fan blades, I went with two 3/8ths bolts. Metrics work, too!
1. File the heads so the mount will fit "almost" properly on the K-frame. I got them pretty thin, but with plenty of strength still there. Some guys have used countersunk bolts, as you can see in the pics below.
2. If you're using your own mount, there's no need to disassemble it from the bracket. Leave it be, as you're drilling through the whole assembly anyway. If you're going with a new mount (even a cheapo China mount will work fine with this mod), bolt it to the bracket, torqued, etc, before drilling.
3. Figure out where you want the holes. Drill a small pilot hole first, then drill the needed hole size in two steps, unless you have a powerful drill press.
4. Insert bolts with heads down, washers are NOT needed. Put a drop of Loctite on the threads (or use a Nylock nut) and run the nut down to
almost touching the mount. Almost! Leave a gap about the thickness of a business card and the mount will function totally normally, transmitting no vibes to the chassis with this small gap.
5. Reinstall, done! This works perfectly, forever.
This link that I found a year ago isn't currently working, but maybe it will come back up.
http://www.dodgecharger.com/forum/index.php?PHPSESSID=auldkin3miv7996f2auvtiec91&topic=13216.0
Here's my pics:
And some pics from various forums: