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Discussion Starter #1 (Edited)
11 inch rear MPB and stock drum weights and measurements

So I decided to get a set of these Master Power Brake 11" drums for the 8.5 ten bolt I am building up for my 71. I was told they were heavy and I knew they would be big, but DANG!! They are huge and heavy.

So now a comparison of three Drums: Stock finned 9.5"X2" off the new 8.5 : Stock not finned off the old 8.2 rear
: Master Power Brakes 11" drums

Please allow some error on weights as I used the digital bathroom scale:rolleyes:

The finned stockers are 3 1/8 X 12" overall
Drum = 15.4Lbs
Backing plate with shoes and ebrake cable = 9.4 Lbs

Not finned stocker off the 8.2 = 3 1/8 X 11 3/8"
Drum = 11.4 Lbs
Backing plate (didnt weigh but should be same as the 8.5 housing plates)

Master Power Brakes ARE 4 1/4" X 14" overall !!
Drum = 24.8 LBs !!
Backing plate with shoes but no E cables =9.4 Lbs
TOTAL FOR DRUM AND BACKING PLATES WITH PARTS = 34 1/2 Lbs

That drum is over nine pounds heavier than the stock finned one and over thirteen pounds heavier than the not finned stocker off the 8.2 housing.

Also the size measurements alone being that it is 1 1/8" thicker it makes it stick 1/4" or so out of a 15X7 stock chevy Ralley wheel.

And it is only 1/4" from the Drum to the stock shock mount. I put one on the car over the stock backing plate. Its like the finned portion of the new drum continues a full inch further in than the actual braking surface as scene from the one photo. this is what puts it so close to the shock mount.

here are some photos, one of the photos even shows the drum completely over the stock drum on my welding table.










So do you think I should run em' or return em cuz of the weight, Ten pounds per side more unsprung weight and Ten pounds more for the axle to try and get up to speed to.:( But I bet the car will stop better though.
Carcass
 

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Discussion Starter #2 (Edited)
How much difference is the ten pounds of rotating weight per side gonna make on my car??

I'd like to know how much weight is saved by going to 11 inch single piston rear disc setup versus stock type drums and these giants.
I should have taken a photo of the drum in my spare rim, I'm not sure that the fins are gonna be much good considering the drum takes up the whole inside area of a 15" Ralley wheel.
 

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Discussion Starter #3
The cooling fins on these drums are massive, that and the additional diameter make up the 10 extra pounds, I wonder how well those fins work anyways.
 

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You could check with MPB to be sure, but I believe there is a smooth (non-finned) drum that will work, and they should weigh about 15 lbs. each.
Let us know if that works out.

Jeff
 

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Thats a big old drum alright. I will probably do the the front disc brake(I have all drum right now) conversion from MPB next year and keep my stock rear brakes(rebuild them of course). I did their conversion on the front of my last 71 and I used to race it all the time.
 
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