Re: did any 3rd gens get a 12 bolt??

by dragons_lair59 Sun Feb 17, 2013 7:44 pm

for guys running 9" rear ends ive heard that ya gotta have adjustable uppers to compensate for the mount locations on the houseing being different the gm rears, is this true?

by 77mali Sun Feb 17, 2013 8:22 pm

All those parts are making me hot.... Very Happy

by carcass Sun Feb 17, 2013 9:01 pm

I hear the chev in a chev plan, but I'd be willing to bet that 9" contains absolutely zero 0 Ferd parts.

by carcass Sun Feb 17, 2013 9:09 pm

quality adjustable control arms seem like a good plan with any decent rear end build, my stockers look like they'd fold up in a second with 400HP and slicks

by WyldeBill66 Sun Feb 17, 2013 10:47 pm

It's still a F-word design...Heavier or reinforced control arms would definitely be a good idea.

by carcass Mon Feb 18, 2013 1:34 am

IMHO the only thing good to come out of the Furd plants was the 9" and the mustang 2 front end design. Early furds with flatheads were great but after WW2 they lost they're edge.
Sides that, who cares, that ferd designed rear is the bomb and we all know it.

by 2fat2fly Mon Feb 18, 2013 2:16 am

Now thats what I'm talking about!! How did you choose your nine inch rearend width?? Did you get it stock width from axle flange to axle flange?? did you compensate for any special disc brake setup for width?? and did you use the stock control arm mounts? Thanks in advance.
I'd bet a guy could spend just about as much on a ten bolt buildup as a nine inch too, well maybe a few more bucks for the nine, but well worth it for sure,
that feeling of an assured foundation for power must be great

The housing is an exact copy of the ones in our cars, it's from Quick Performance and they were great to deal with, yes the width is the same and you can go with either the disk or the drum style. The disk naturally is a bit higher, I chose to go with the factory drums on the back and had my shoes relined with semi metallic material and works great when slowing this thing down. the control mounts are the same, if yuor using the sway arm it will have tobe trimmed to clear.
If you have the corporate 10 bolt (after 72) depending on the grunt of your car, I would thing putting in some good axles. As far as the c-clip eliminator kits,take your time when installing and make sure all your flanges areas are true and they won't leak.
the complete diff. in my car is about $2500.00, not cheap. I had to go with what I thought would hold up!!

by carcass Tue Feb 19, 2013 11:02 pm

I think those bills were wel spent 2fat2fly!
Sinking money into a ten bolt seems like a futile effort, they can be built fairly stout but the money it takes is similar to a crate rearend,
Please correct me if I'm wrong
Richmond gear and set up kit $280 Jegs
Eaton Posi $490 Jegs
Moser axles 30 spline $260 Moser
Moser support cover $160 Moser
1350 forged input yoke $135(optional but 1310's suck)
Labor for setup if you cant do it yourself $200??
Have the tubes fixture TIG welded to the center section $100?
Leaving out c clip elimination ends or Furd bearing ends welded on brings my total estimate to
$1625.oo with c clips still in the diff, add a hefty chunk to chuck those.

I'd say 2500 for the ferd 9 is well spent, my only gripe with the 9" is it reportedly robs about 3% of your horsepower while the 10/12 bolt design is more efficient, but the 9" is a brute for strength, and you can swap third members in half an hour, I'd say its worth it for sure.
so the difference between my estimate and 2fat2fly'a awesome build is
$875 dollars, save some money by not buying $1500 rims and tires right now and build a foundation, thats my plan.

by jtenn Tue Feb 26, 2013 4:03 pm

Two points: I found a 1/2 price Eaton Tru Trac on the Summit discount shelf.
Took it to a friend at Drive line Service here in town to see if they could alter from stock 2.73 10 bolt to 3.36, (Torsen type) with proper bearings and larger axles? They did. Total came to <$1300. plus <$275. at Summit.
Almost ready to start driving her as restoration will be done this weekend. 2 1/2 years a ?$.

by pila Tue Feb 26, 2013 9:54 pm

I have a 9-inch in my Elco project, from Currie, built to fit. But.....I had to shorten one of the adjustable upper control arms, since the rear end isn't anything like a GM set up, and I didn't have enough adjustment.
If I was running a small engine, I would never buy a 9 inch, but a torque monster would likely tear up a 10-bolt in short order.
And a Currie isn't cheap.

by carcass Tue Feb 26, 2013 11:39 pm

pila wrote:I have a 9-inch in my Elco project, from Currie, built to fit. But.....I had to shorten one of the adjustable upper control arms, since the rear end isn't anything like a GM set up, and I didn't have enough adjustment.
If I was running a small engine, I would never buy a 9 inch, but a torque monster would likely tear up a 10-bolt in short order.
And a Currie isn't cheap.

Thats interesting that you had to shorten the upper control arms because you ran out of adjustment due to the ears on the 9" being located differently in relation to the axle centerline?? What control arms do you have? I like the look of the Detroit Speed control arms, and wonder if they'd work with a Currie 9", do you think its possible that each of the major 4 9" distributors locate the control arm mounts on their products in different locations?? Like say I bought a Strange housing would the upper mounts be different than the Moser mounts or Quick Performance??

As far as not buying a 9", I can see saving a few bucks on a ten bolt build, but most of my buddies are going to the 9" in their hotrods and it just seems like the way to go, swapping third members around and all. IMHO if your gonna rebuild a ten bolt with anything more than takeout used gears and posi units, why not spring for the 9. I respect guys using the cop car diffs but those require mods as well I hear.

by carcass Tue Feb 26, 2013 11:44 pm

I still havent phoned Moser to see if they make axles for the press bearing ten bolts but I spose they do. I almost fell over when I pulled my first axle out of a ten bolt and looked at all the porosity and the ludicrous tapered area 5" down from the c-clip groove. Amazing they hold up as well as they do, also who's briliant idea was it to make the actual axle a wearable bearing surface on c-clip axles?? Is it lower production cost?

by carcass Tue Feb 26, 2013 11:56 pm

I'd really like to see if anybody used a dana 60 in a third gen, that would own.

I also saw the Cale Yarborough car for sale on ebay has a 9" so a guy could justify the furd swap buy saying your cloning a legend.
http://www.ebay.ca/itm/Cale-Yarborough-Junior-Johnson-442-NASCAR-11-/281059313671

by w451973 Mon Apr 22, 2013 2:32 pm

How much power do you plan on making ? You already have the better 10 bolt with the bolt in axles. You can get the good axles with better bearings from Moser. A 9 inch is great to brag about Laughing

but alot of people that buy them don't even have the power to break a 10 bolt. They only got bad reps because nobody made quality parts for them years ago like they do today. You also don't want to forget the extra weight of a 9 inch over your 10 bolt.

The 10 bolt in my 75 Cutlass I had handled many 10:60-10:70 passes without any problem.

did any 3rd gens get a 12 bolt?? - Page 2 75rearfuel

did any 3rd gens get a 12 bolt?? - Page 2 75rearfuel

by carcass Wed Apr 24, 2013 3:10 am

w451973 wrote:How much power do you plan on making ? You already have the better 10 bolt with the bolt in axles. You can get the good axles with better bearings from Moser. A 9 inch is great to brag about but alot of people that buy them don't even have the power to break a 10 bolt. They only got bad reps because nobody made quality parts for them years ago like they do today. You also don't want to forget the extra weight of a 9 inch over your 10 bolt.

The 10 bolt in my 75 Cutlass I had handled many 10:60-10:70 passes without any problem.

Thanks for the reply and photo!
cool shot of those tires,
Good news on better axles from Moser, the stock ones look like twigs I swear.
I hear you on the how much power do I have thing, I'm sure I wont be making enough to really need the 9" it just seems to have a lot of bonus points going for it.
Do you or anybody know where I can get an aluminum support rear cover for the B.O.P. ten bolt that has the cover with the two C shaped cutouts in line with the axle tubes??

by carcass Wed Apr 24, 2013 1:25 pm

w451973 wrote:How much power do you plan on making ? You already have the better 10 bolt with the bolt in axles. You can get the good axles with better bearings from Moser. A 9 inch is great to brag about but alot of people that buy them don't even have the power to break a 10 bolt. They only got bad reps because nobody made quality parts for them years ago like they do today. You also don't want to forget the extra weight of a 9 inch over your 10 bolt.

The 10 bolt in my 75 Cutlass I had handled many 10:60-10:70 passes without any problem.

I called Moser today and the guy on the tech line had basically no idea what I was talking about, he replied to my questions with "Yah, youd have to send that type of axle in for us to duplicate" he said "thats an odd sounding rearend we don't know anything about those axles"
I also asked him about a rear cover for these rearends that got the odd cover with the c shaped cutouts and he replied "yah, we havent seen anything like that hear"
His customer service was poor, its commonly known that the B.O.P. style rearend was made not only in first and second gen A bodies but also through the third gen as well, I feel that a guy in the customer service dept. of the biggest name in rearends would at least have a look on the internet or have heard and have a better answer than we havent heard of that and then send the customer packing. Pretty lame.
I'm going to start a whole new thread just about B.O.P. axles so maybe we can get some info about these things going and a database of knowledge of where to get regular and aftermarket parts for them.

"

by JB2wheeler Thu Apr 25, 2013 12:30 am

I have a BOP rear in my 74 Elky from the factory. I upgraded it with a 3.42 posi and Moser 30 Spline axles. Funny thing, you must have got the janitor on the phone. JB

by carcass Sun Apr 28, 2013 11:10 pm

JB2wheeler wrote:I have a BOP rear in my 74 Elky from the factory. I upgraded it with a 3.42 posi and Moser 30 Spline axles. Funny thing, you must have got the janitor on the phone. JB

would you mind seeing if you still have a part number for these axles?? I am going to write Moser a letter and include a link to a thread I am starting called the big buick olds pontiac 8.5 ten bolt info/tech thread.

by JB2wheeler Mon Apr 29, 2013 10:19 pm

Maybe you could order the axles thru a speed shop. That way they would be responsible for getting the right axle for your car. When you buy direct from the main man (Moser, for example) you do not nessessarily get the best price. A speed shop gets the part from the main man at a discount and you pay retail, which in MOST cases is the direct price. Check it out. JB

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