8 3/4

-
M

matty mopar

Well-Known Member
Joined
Jan 17, 2011
Messages
104
Reaction score
1
Location
New York
Now I know that Mopar gave you a Dana 60 if you had a 440 or hemi with a manual. My question is, what kind of power can an 8 3/4 take?
Can they be built up, and which is the strongest of the three cases?
 
the 8 3/4 came in Hemi and 440 auto,s.They can be built with stronger axels,billet parts,race gears,bigger studs.What are your plans to throw at it,HP wise?Strongest in my opinion is the .489.
 
X2 on the 489, just ditch the stock crush sleeve for a solid one and you'll pretty much make it bullet proof.
 
500hp stock
up to 600hp: 35 spline axles,back brace
after 600hp: aluminum third member

They will hold alot of abuse but you will need to change/adjust gears alot. On launch the gears will try to get pushed out the back of the case. The pinion gear seperates from the ring gear. This will either break the teeth or wear them out. Even with the upgrades you have to adjust the gears all the time. The back brace and aluminum third member almost cures this. The support cap bolt go all the way through the third member so this helps with the gears seperating. But only 3 of the bolts go all the way through. The 4th one can't because of the way the third member case is disigned. Dave Dvorak uses a 8 3/4 in his cars. Not sure on his ET's but I think they are in the 8's
 
My buddy ran his all steel (Except hood) 69 Dart with a 500 cune Indy head monster into the low 9's on a regular bassis for a long time. It did fail after sometime.
 
Sorry, a bulletproof 8.75 case does not exist.

You could throw 700hp with 14x32's at one if it's in a 2000lb roadster. Put that same set up in a 3700+lb car off a brake and you'll get a different result.

Any of the cases are serviceable within reason.
 
I use an aluminum case in my 8.75 along with the pro race gear, 4.86 is the only ratio available in a pro gear though. The 742 case has probably the largest rear pinion bearing of any passenger car differential so it is the strongest.
 
I would probably throw somewhere around 450-500 hp with a 4 speed. Would a stock 8 3/4 with a 489 case hold up to this? The car would be raced, but only 10-15 times per year.
 
I would consider putting a brace on, heavier bearing caps and upgrading your axles at the very least. A buddy runs a shortened one in his car 2600 LB race weight, around 600 HP launches off the trans brake around 3500 RPM's. To my knowledge he has not had any issues in several seasons.
 
badsport said:
I would consider putting a brace on, heavier bearing caps and upgrading your axles at the very least. A buddy runs a shortened one in his car 2600 LB race weight, around 600 HP launches off the trans brake around 3500 RPM's. To my knowledge he has not had any issues in several seasons.
Click to expand...

To do all that work, would it just be cheaper to find a Dana 60 and shorten it to fit an A-body?
 
X2 on the Dana Build

It maybe overkill now, but in a few years when you need it then you have it. Plus you never have to worry is this going to be the launch my rear breaks.
Spend a little more now or spend twice as much doing it over later
 
matty mopar said:
To do all that work, would it just be cheaper to find a Dana 60 and shorten it to fit an A-body?
Click to expand...

If your starting from scratch then go the Dana route. I was answering your original post. If you have the 8 3/4 now then you can build it to suit your needs until you get a Dana. I'm thinking a Dana is going to cost you more. I bought and built an 8 3/4 with back brace, upgraded the ring and pinion, all new bearings and seals, rebuilt the suregrip, longer wheel studs etc. for around 600 bones. It did however take some time to pull the parts together as I was trying to get the best deals I could.
 
badsport said:
If your starting from scratch then go the Dana route. I was answering your original post. If you have the 8 3/4 now then you can build it to suit your needs until you get a Dana. I'm thinking a Dana is going to cost you more. I bought and built an 8 3/4 with back brace, upgraded the ring and pinion, all new bearings and seals, rebuilt the suregrip, longer wheel studs etc. for around 600 bones. It did however take some time to pull the parts together as I was trying to get the best deals I could.
Click to expand...

that would probably be my route
im not sure if I can find a good dana 60.

The old dana 60s were a lot stronger than the new ones right?
 
Dana 60 is a Dana 60, there is the Dana 60 car and the Dana 60 p/u truck and the Dana 60hd.
The HD had the bigger axles and are in 1 ton trucks and clearly had HD cast into it, 35 spl, and bigger bearings, heavier wall tubes.

Other than that the Dana 60 is a Dana 60.

Only on front axles for trucks are there a NEWER is better than OLDER issue with the Dana
 
You must log in or register to reply here.
-

Back
Top