Another, what is it?

[Paul G]

What is it, and why is it there? I have a real good idea that it has something to do with smoothing out vibrations, like a vibration damper of some sort. I noticed that it had a lot of movement and would "clunk" against the floor when I pushed up on it. The rubber isolators are shot I would think. Are they replaceable? Removed it for now. And it was quite heavy.   

[hemihead]

Yep , a vibration dampner .

[Ghoste]

Now that I know what is it, I have to ask where is it?

[Paul G]

Now that I know what is it, I have to ask where is it?

Above the drive shaft bolted to the underside of the floor.

I wonder if it is something that is needed or just 10# of ballast.

[TUFCAT]

I've heard (or read) that Chrysler mounted these to cure something the engineers referred to as "B-Body Boom". This was a noise phenomenon inside the vehicle set up by certain road harmonics.  These brackets were also called elephant ears, used in the late 60's/early 70's. That's all I know.

[Ghoste]

I thought that was just the pinion snubber hitting the floor during shifts?

[Alaskan_TA]

Boom damper. See the three page TSB at;

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%201.jpg

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%202.jpg

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%203.jpg

[Indygenerallee]

Ive seen them mounted on a few 727 tailshafts also.

[chargd72]

Do you think these are necessary if you're putting in subframe connectors?  You'd think those would get rid of a lot of the vibrations down there.  Plus, it would be nice to lose 13 lbs.

[Ghoste]

If you are doing a performance build, would you hear the "boom" anyway?  I wouldn't worry about myself and chalk it up to the times.  Performance was dying and luxury was coming in about the time this thing showed up.

[chargd72]

Good point.  Off it comes!

[Mytur Binsdirti]

They screwed everything up with the 71 & later cars.   

[Paul G]

Boom damper. See the three page TSB at;

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%201.jpg

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%202.jpg

http://www.hamtramck-historical.com/images/TSBs/1971/D71-23-11%20Page%203.jpg

Great info. Thanks. I will see if there is any difference in the car without the damper. Probably, the headers and 2 1/2" exhaust with turbo mufflers negate the "boom" all by themselves.