Ford 9in? Or beef up the 8.75?

[gunnyx69]

Just wondering yalls opinion, and if anyone has done a 9in swap. I just got this terrible clacking noise when at high rpms and when I let off the gas. Also when I let off the gas my whole axle shifts down a little bit. I haven't taken anything apart yet, just put it on stands and found the noise. Oh yea, the manual trans, clutch, flywheel, shifter has all been re-done on this stupid 3 speed.
So I'm kinda wondering if you have an idea what the issue is? And if its better/ cheaper to beef up the 8.75 or a ford 9?
Also I need an axle that can handle high horsepower and torque for when I put in the stroked 383/727tf combo.

[soopernaut]

Why 9 inch? Why not another 8.75 if you don't want to rebuild yours? They put the 8.75 behind Hemi cars. Just because the ring gear in the 9 inch is a quarter inch larger doesn't mean it is a better axle. It does have much better aftermarket support but you shouldn't have any trouble finding parts for an 8.75 axle.

[nytemuvr]

Actually they put 9.75" rear ends in Hemis and 440-6 cars(b & e-bodies), 8.75s should be good for 500 hp nominally, if beefed up some. Unless you're drag racing it, 8.75"s should be street worthy.

[gunnyx69]

I definetly will be doing a lot of drag racing once the big blocks in. And eventually will put a supercharger on it. So I'm not sure how much HP I'll be working with. Probly more than 500 I'm guessing. I've never heard of the 9.75, sounds worth looking in to. Has anyone beefed up the 8.75? Or done an axle swap?

[nytemuvr]

I definetly will be doing a lot of drag racing once the big blocks in. And eventually will put a supercharger on it. So I'm not sure how much HP I'll be working with. Probly more than 500 I'm guessing. I've never heard of the 9.75, sounds worth looking in to. Has anyone beefed up the 8.75? Or done an axle swap?

[Hobcobble]

Actually they put 9.75" rear ends in Hemis and 440-6 cars(b & e-bodies), 8.75s should be good for 500 hp nominally, if beefed up some. Unless you're drag racing it, 8.75"s should be street worthy.

I believe they did use the 8.75 corporate axles in Hemi and 440+6 cars too.... Didn't they?
John

[kurt]

Dana 60, 9.75 ring gear from wiki. I had a 1969 R/T Charger with one.

Dodge
1966–1970 Coronet & R/T
1966–1972 Charger & R/T
1968–1972 Super Bee
1970–1971 Challenger
1963–1993 Dodge Ram 250 and 350
1994–2002 Dodge Ram 2500 (V8 Only)
2004–2006 Dodge Ram SRT-10

Plymouth
1966 Belvedere
1966 Satellite
1968–1972 Road Runner
1967–1971 GTX
1970–1971 'Cuda

[nytemuvr]

Actually they put 9.75" rear ends in Hemis and 440-6 cars(b & e-bodies), 8.75s should be good for 500 hp nominally, if beefed up some. Unless you're drag racing it, 8.75"s should be street worthy.

I believe they did use the 8.75 corporate axles in Hemi and 440+6 cars too.... :thinking Didn't they?
John

I don't believe so. When I ordered my '72 Challenger the lowest gear was 3.55s(8 3/4s), later I changed to 3.91s. It wasn't an option to get anything lower or any other rear axle after '71. The 9 3/4s had 3.54s, 4.10s and lower gears and no BB for '72 Challengers. My interchange book doesn't show a 9 3/4s for '72(e-body) and only 9 3/4s for the Hemi and 440s in '70-'71s. It was part of the Scat-pak option in '70-'71, if I remember correctly. I think a beefed 8.75 would work with 500 hp, but not much more. This interchange section is for axles and housings with the same info for '68-'72 b-bodies.

[Hobcobble]

Very interesting! I didn't realize this. Great information.
John

[RussRoth]

I believe they did use the 8.75 corporate axles in Hemi and 440+6 cars too.... Didn't they?
John

The early ('64+) Race Hemis were 8 3/4 IIRC but later ones were all 60's I think. The 440 4 speed cars were 60's also but the autos were 8 3/4. This is going off memory from "back in the day" so it has a been a year or two.

[dodgeboykim]

I believe they did use the 8.75 corporate axles in Hemi and 440+6 cars too.... Didn't they?
John

The early ('64+) Race Hemis were 8 3/4 IIRC but later ones were all 60's I think. The 440 4 speed cars were 60's also but the autos were 8 3/4. This is going off memory from "back in the day" so it has a been a year or two.

That's basically the way it was.

[Jim100]

I would look around for a dana 60 perhaps. But a 8.75 is a pretty strong unit and easy to swap gears around.

[dodgeboykim]

Original Dana 60 car diffs are near and dear. They can get to be pretty pricey . Another option is the poor mans Dana 60 car where you take a truck 60 and change the tubes out for car tubes and go with custom axles or have one built from say http://www.currieenterprises.com Or some other custom axle manufacturer.
The one thing about going to a 60 although extremely bulletproof is gear changes are a big job. 8 3/4 Diff is an easy pumpkin change.

[soopernaut]

Actually they put 9.75" rear ends in Hemis and 440-6 cars(b & e-bodies)

They also used 8.75 axles in Hemi cars like I previously stated.

Below is for 69 Chargers-The 3.23 and 3.55 ratios listed for the Hemi cars are 8.75 axles.

[StinkFinger]

If your not breaking stuff I wouldn't throw a boat anchor of a dana 60 in. The ford 9" is plenty strong and way lighter and an 8-3/4 wil be just as strong and keep it mopar

[66patrick]

The 8-3/4" WAS used behind all automatic Hemi and 440+6 cars unless a Dana 60 was special-ordered!!!

The Dana 60 was behind all 4-speed HEMI and 440+6 cars.

I've owned a $h!tpot full of '64 - '74 Mopar cars and trucks to know this to be a fact, plus there is plenty of documentation out there to back my statement up.

Dana 60 car axles are friggin' EXPENSIVE! And heavy, to boot! Unless I were restoring a numbers-matching Hemi or 440+6 four-speed car, or could get a known good Dana 60 for cheap (<$1K), I'd just pass a Dana 60 by, quite honestly!

As far as the 9" Ford vs 8-3/4" Mopar axles go, go with what you want to! Prices for the Ford axle are a bit less than the Mopar axle, plus parts availability for the Ford is a LOT better than for the 8-3/4" Mopar unit. The 9" IS a better axle, guys, face it. If you really NEED to stay "all-Mopar", then your mind is made up and that's that. But, for the money spent, the Ford axle is a better deal, and a better axle than the 8-3/4". That's the way it is. The 8-3/4" axle production ended forty years ago. You can buy NEW Ford 9' complete assemblies. Granted. the end use is going to matter. For serious racing, the Ford axle is the only way to go. For a resto, or if you are not running 500+ hp at the wheels, then go with the 8-3/4".

[soopernaut]

The 9" IS a better axle, guys, face it. If you really NEED to stay "all-Mopar", then your mind is made up and that's that. But, for the money spent, the Ford axle is a better deal, and a better axle than the 8-3/4". That's the way it is. The 8-3/4" axle production ended forty years ago. You can buy NEW Ford 9' complete assemblies. Granted. the end use is going to matter. For serious racing, the Ford axle is the only way to go. For a resto, or if you are not running 500+ hp at the wheels, then go with the 8-3/4".

How is it better? Many people would say the opposite, especially in stock form.

The Mopar unit has a better pinion angle, uses less horsepower to turn, has better bearings, is lighter in weight and 30 splines vs 28 on most 9 inches. The axle housing would probably need bracing and a pinion snubber for severe use.

[Roxyflash]

For what its worth ever look at a ford 9 inch they need a small bearing to help support the pinion on the gear end as the front bearings are small.If you use the 8 3/4 look for the older clutch style suregrip.I run them and have stripped both the spicer 60 and 8 3/4 in the trucks I guess im hard on stuff.The good thing is the 8 3/4 are so easy to work on and there everywhere all you have to do is look around.The gear ratios are plenty to road gear to strip gears.

[66patrick]

How many 8-3/4" axle housings are around??? How many Ford 9" axle housings are around??? Break a Ford, you get another. Break the 8-3/4", and where is that axle again??? For pure economy of build, the Ford wins. The differences are MINOR, and not deal-breaking, in my book.

[Roxyflash]

I just go into my shed and get another axle I have only stripped two axle so far I wont put a ford or chevy part on my sweptlines all Dodge only aftermarket is on the engine and that's just headers carb and intake the rest all mopar.