see post #20 there are other optionsIf your modded in any way than your gonna have some movement regardless and on that note stock mounts are barely strong enough for the stock motor. The ZZP tranny mount is the only poly tranny mount available for our 3800 and is one of the few solutions to our motor/tranny movement.
I would think that the guys who are putting down some power have found a way to keep their motor to minimum movement. Hopefully they'll chime in soon.....
If you're willing to spend the money or find an LS4 powered W-body donor at the junkyard...
You can get a differential cover transaxle mount which mounts on the passenger side of the cradle.
Simple the poly block I used in the writeup was solid and all you do is drill two holes. I still am running with no issues an no cracksDamn, both the write up and LS4 passenger cradle mount sound like great ideas but there's gotta be something simpler. May be there isn't a simpler way but I know a lot of 3800 drivers that are putting down some power that aren't using either of these ideas with minimal motor movement. Now either they're getting some major movement or they have a custom mount supporting that backside near the firewall.
I may try doing that write up as it sounds very effective, now it appears to look just like ZZP poly trans mount so what internally would keep that home made poly mount from cracking as the ZZP one does as they're both made and supported with polyurethane so there's no real difference or is there?
It might sound ghetto but why not either lock wire over the whole mount or use a hose clamp. To keep the mount from wanting to pull apart and crack. I'm pretty sure thats probably the issue is the both sides of mount wanting to pull in opposite directions during hard acceleration thus causing the crack.