This guy gave my friend a rear end for some house work. He said it was a 9 inch, but the ring gear doesn't measure 9 inches. Then the guy said it came out of a Falcon, and it looks just like a 9 inch! Does anyone know what looks like a 9 inch but isn't? And, are axle upgrades and lockers available? Thanks

Chris

Yep, you got a Ford 8" rearend alright. The 8" is the 9"s little brother. It came as standard equipment in Mustangs and Falcons. Most people see a ford rearend with the removable chunk, and think "it must be a 9". What most people don't know is that the vast majority of small to midsize cars in the sixties came with the 8". The only cars to get the 9 back then were fullsizes and the super-performance models.

You may be happy to learn that the 8" is actually quite a beefy little rearend. It is smaller and lighter than the 9", but shares the same axleshafts as a 28 spline 9" (they are interchangeable, in fact). It also has a similar bolt pattern on the chunk, and I have heard of Mustang guys sticking a 9" third member into an 8" housing for a lightweight "sleeper" heavy-duty rearend. The 8" is good for up to about 250-300 horsepower in stock form, and there are several different kinds of lockers available. If you're putting it in a car, it's a great rearend, but for a truck I'd reccomend finding an acutal 9".

ahhhhhh another attack of the 8"

IMO, they are strong enough to use behind a go cart

My buddy was planning on putting the 9" in his Cherokee. Will the 31 splined 9" axles fit in the housing with the 9" chunk? Also, the weekest part of the 8" is the 28 splined shafts, correct? I can do a search now that I know what he's got, thanks!

Need help again! Did a search but didn't find anything for the 8". Is it the 8.8 or just the 8"? I'll keep trying to search for the 8" Ford rear, but the search says I'm not using 2 words or more.

8, not 8.8, which has an 8.8" ring gear and is easely distinguishable from the 9" because the housing is isn't circular like the 9"

Originally posted by welndmn
IMO, they are strong enough to use behind a go cart


Perhaps your definition of a go-kart varies from mine, but I've found that the 8" holds up to repeated drag racing in my '69 Mustang.

It has the 8" with 2.84 gears (yeah, yeah, I know they're highway gears, but I need the gas mileage as this is my DD also). The abuse I subject it to (At Speedworld dragstrip in Phoenix) is:

3150 lbs race weight
Built 289
30lb flywheel with 11" clutch
3500 RPM clutch dump






Originally posted by:EMIEVEL
My buddy was planning on putting the 9" in his Cherokee. Will the 31 splined 9" axles fit in the housing with the 9" chunk? Also, the weekest part of the 8" is the 28 splined shafts, correct? I can do a search now that I know what he's got, thanks!


That all depends. First of all, you'd have to see if the 31 spline axles use a tapered or a regular roller bearing, and if the bearing is the same OD as the 8" axle bearing. If they are the same, and the length is the same, I don't know why you couldn't do it. If the bearing is different, get out the calipers and measure the bearing press area on the axleshaft, and see if an 8" axle bearing could be pressed on the 9" axle instead. Finally, I'd just reccomend trussing the housing under a rig, as it could be loaded heavier than a car could.

You COULD do this if you already have the parts, and don't want to spend money buying no parts, and granted this would be kind of cool, simply as an experiment, but it's really alot of work just to make an 8" housing into a 9" housing when you could probably go the junkyard and find a 9" housing of proper width for less than $100.

And yeah, the 8.8 is a totally different axle from the 8". The 8.8 is an integral carrier axle, like a Dana 44, and the 8" is a removable carrier, like the 9". (Not to mention the difference in size of the ring gear :rolleyes: ). Check out the summit catalog. Or go to the www.summitracing.com website, and go thru the categories until you get to rearend parts. Checking their website under that category, and scrolling down until I see "Ford 8 in. ring and pinion set", I see that they have them from Richmond gear in ratios as low as 4.62:1.

Here is teh fast way to tell 8" or 9" They look the same, except the bottom bolt that holds the center chunk in. On the 8" you can use a socket with out a problem, the 9" you need to use a wrench or swilve socket on it.

There is also the 9.75"(or close to that). Just a rarer and stronger version of the 9". The only problem with this rear is that it is so rare that you can't get any after market parts for it. Just to give you an idea of how hard they are to find. A good friend of mine sells right around 75 9" chunks every year. He has only ever pulled 2 of the 9.75.