I was at the wrecking yard today looking for a rearend for my model A roadster. It will have a 331 Hemi for an engine. I found a Ford Bronco of the smaller type. What rearend do you think that it has? What cars should I be looking for that would have a 8 or 9 inch in it?
What year bronco? Early ones have 9" rears. An 8" has a slightly flatter bottom than a 9" and on an 8" you can access all bolts with a socket. On a 9" there is one at about 7:00 that a socket cannot get to. A wrench is necessary to tighten or remove it.
Kracker36 nailed it. I had a 68 Fstbk GT 390 with a 9" and I currently have a 1978 Mustg II 8" converted to a 4-link under my special construction car.
Also, a later Bronco II may have an 8.8" rear. It has an inspection plate in the rear------unlike the 8 and 9 which have a " chunk " that comes out from the front.
If by "the smaller type" you mean a Bronco2 (~84-90) then it will have a 7.5" (early) or 8.8" (late). You don't want a weak 7.5", but the 8.8" is the same tough unit as an explorer or 5.0 mustang. They don't look traditional though. The early small Bronco (66-77) has the 9" you want.
A lot to look at. Scroll down a bit, 1/3 to 1/2 way, and there are pictures and descriptions visually comparing 8" and 9" indentifications. http://www.maliburacing.com/ford_9_inch/ford_nine_inch.htm Bill
An 8in behind a 331 Hemi with anything much more than stock HP is not going to like being used hard. 9in is strong, readily available, but fairly heavy and considerably bigger. The steep hypoid angle (pinion drop from axle centerline) is said to result is greater parasitic losses than some other axles but I don't have details on this. 8.8 looks very different, has a cast center section and a bolt on rear cover, plenty strong for most purposes (the current production 600HP GT500s run an 8.8) but as others have noted it's not particularly attractive, like the 9in the bits come in 28 and 31-spline flavors from Ford and even stronger stuff in the aftermarket. Uses C-clips, in the corner-turning world it's long been common to put 9in ends on the housing and use shafts with 9in bearings and press-on retainers so the axle mostly stays in the housing if something breaks. Gear setup requires different tools (may need case spreader, etc.) than the removable-carrier 8in/9in.
Contrary to internet legend, the 8" rear is not made of glass and will easily handle a 331 Hemi. It's stronger than a GM 10 bolt and falls between a 10-bolt and a MOPAR 8-3/4 rear as far as strength (close to the 10 bolt). Like the 9", one of the things that makes it strong is the third bearing supporting the pinion nose and preventing deflection. The 8" is one of the most underrated rears out there. Ratio availability is the biggest limiting factor and the laws of supply and demand make ring and pinions expensive, but setting them up is very similar, if not identical, to the 9". Lockers and limited slips are also available...and pricey. If you can't find an 8" with a decent ratio and a traction-lok already, it'll be spendy to convert it and for the same money, you can get a 9". The 9" is bigger and heavier - if you're running a hemi, you're not worried about parasitic losses of the rear.
FACT ... Whenever Ford Motor Company made cars with 8 inch Ford rear ends ... the horsepower did not exceed 250 HP or so. When the Mustangs and Fairlanes got the HP 289 with 271 horsepower, Ford went to the factory installed 9 inch Back when 64/66 Mustangs were on the street everywhere ( late 60's early 70's ) I saw a lot of 8 inch Ford rear ends broken. A 57-58-59 Ford 9 inch is a bolt in for the early Mustangs and MANY, MANY were upgraded to the 9 inch because the 8 inch failed. Why possibly worry about the strength ... of a 8 inch when a 9 inch is so easy, available and has a much better choice of gear ratios.
The 8.8" Explorer has factory disc, with the "hat rotors", incorporating a built in parking / emergency brake. Bonus; Parts readily available anywhere. 4TTRUK
The 9-inch in the warly Bronco is a good one to get. Has the 5 x 5.5 bolt pattern. It is 28 spline axles I think, but with street tires you will not break anything. Tires will break loose before something breaks. 8-inch does have limits, but I tend to agree with the opinion that small block is OK, big block is not. Your 331 is closer to a small block, and assuming the same street tires, it should be able to hold up. Auto trans is easier on the rearend than a manual trans. I would try to get 9-inch, that way you will not have any worries.
nine inch is the only way to go! You know that you are going to beat on it a little so you might as well source a nine inch! Lots of different gear choices to pick from too! Jay
early bronco 9in is nice .the 74 thruogh 77 years have big and small axle bearings. if you get a small bearing 9in you can run 8in axles in the 9in housing .all the early bronco had 28 splin axle .you have to find the right lenghts to fit mustang axles work.thats what I put in my 9in for the small ford bolt pattern. the bronco rim bolt pattern is the f150 truck .
Been building and trashing Fords for most of my adult life.... an 8" is NOT a weak diff... I've run one behind a 400 to 450 horse engine without too much issue....granted, not normally sticky slicks and constant burnouts... but definitly strong enough....the 9 inch is the preferred for constant abuse and high horsepower.... as said above many 9 inch rear have the 28 spline axles similar to the 8 inch.... stay away from the 7.5 inch... The 8.8 is also a great rear... running one behind an OT twin turbo car, and it holds up just fine...not too traditional looking though... Behind a 331 hemi the 8inch will do just fine
Relax. I never said the 9" wasn't strong, just dispelling the myth that the 8" is too weak for anything. I've seen 9" rears broken by engines with <250HP - it's all in how it's abused. I'm certain we can all point to various parts that are supposedly the strongest/best that have failed in unlikely applications though. My post actually favored the 9 by pointing out how expensive an 8 is to build when you can run a 9 'off the shelf' or 'from the junkyard' if you know what you're looking for. ...and it's going behind a 331 Hemi, not a blown 426. I've run early Mustangs and hot rods, always with 9, but that doesn't mean I wouldn't run an 8 if the right one came along and fit my application...
I'd say you want a NODULAR third member case in a 9" ford. The regular case is just as apt to spit out the pinion as an 8" is. Just ask DW Ok maybe a regular case 9" is a touch stouter - but if you want strong get nodular. If you went with a nice aftermarket 8" third member case I think you would be able to put plenty of power through it. Lighter rear smaller size - more clearance - some benefits. I had a regular 8" Ford with 3:90 gears behind a 700HP blown small block and a 4 speed and it lasted a long time spinning big old heavy hurst cheater slicks. Survived track passes and lots of 30 MPH burn outs dumping the clutch. It wasn't until it was about 30 degrees outside and I decided to do a burnout and it exploded. I think the main reason it went was because it was so cold and I didn't warm anything up. Just pulled out of the parking spot then hit it. I've got a nodular 9 now. Could have built the rear end I have now the first time and saved half my money.
Bert is the only one that addressed width. First question I would have is fenders or not? The Maverick 8" is 56.5" wide and in the 9" the 57-58-59 Ford Wagon is at 57.25" and the one to look for and getting very hard to find. Any others may have to be narrowed so your A doesn't have the wheels/tires sticking out like a cartoon car. By the way I put an 8" Maverick in my 40 pickup with a torque monster 401 nailhead. But I drive like a little old man.
With 9"ers being so plentiful and easy to narrow, if need be, I personally use them in every build. Mock up the tire and wheel combination you're going to use under the car, measure the distance between the wheel mounting surfaces to get the overall length you need, narrow the housing, send the axles to Moser to be shortened and resplined and your home. I know that is a little simplified but you get the idea. This way you get the EXACT width you need.....no compromises and strong enough to take a blown Hemi. Frank
I picked up a 9 inch for my Model A not because I am going to run huge horsepower or abuse it that much but for the dead nuts reliability and ease of getting parts and picking gear ratios. You loose a wheel bearing on a trip with one and they are easy to find and fairly simple to change and you don't stand much chance of loosing an axle in the process as you would with a Nova or Camaro rear end. Loose a ring an pinon on a road trip and some wrecking yard will have a center section that you can bolt in and go. It might not be the right gear ratio but it will get you home and then some.
The model A I own is running an 8" out of a Ford Mavrick, it fits in perfect. It's powered by a 302 Ford small block with a little work. I use it as a daily driver. I can't squawk at the 8".
thanks for the link ernie. 8 inch is pretty good but of course 9 inches is better just ask any woman................maybe thats why my wife left............
It makes sense if you're building heavier cars with enough underfloor clearance but in something A-size or a lot of other smaller cars there's a lot more bulk and unsprung weight in a 9in than in an 8in.
According to my Chart, 28 to 31 Ford Car & Truck measure 57 1/2 " Flange to Flange. '75 to 80 Ford Granada W/ 8" axle '57 to '59 Ford 9" is a natural, very rare, but best '71-74 V/8 8" All '75 to '77 6 & v/8 's Maverick 5 Lug 8 3/4 " Early Mopar Muscle Car Rear End will work great for that Mopar Engine. Just Old School idea !
i got a nice 8" posi five lugger out of a "grabber" maverick for my 40 coupe. it's allready the right width for my 8-1/2" et's, and the spring perches are in the right spot. maybe not angled right, i dont know yet.
Hi all, I used the 8.8 as is in my big block 70 Nova, no issues even at the drag strip. It is a bargain $300 complete with brakes and springs. Does anybody know if I could use the same in my 40 Ford pickup, leaving the diff off center.
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