8 3/4 or Dana

[91r/t]

I have a 500hp stroker in my 68 Charger with a 4 speed and it has a 8 3/4 rear in it no problem. It has 3.91 gears in it as well. It all depends if your running street tires or slicks. If you have street tires and no traction nothing breaks usually just smokes the tires like mine. if you start doing trans brake/clutch drops and have slicks, then you have a bigger issue to deal with and should probably go Dana. For a street car with little traction and burnout machine the 8 3/4 will hold up fine.

 

[moparnation74]

Dana for me.....

 

[rumblefish360]

Kerndog & 91r/t have a point on power, cars weight and traction. A friend of mine ran a 8-3/4 behind a 500 stroker in a all steel ‘69 Dart. The car was a bit heavy for an A body. A full street interior car.
It did last through weekly drag racing for a season running high 9’s. Then boom! A Dana replaced it and that was that.

I can say if the 8-3/4 would have lasted in a lightened race weight A body. The amount of torque, when & how it is applied and traction or lack there off are the issue points that we’re not really aware of.

 

[91r/t]

Yea we have a 8 3/4 with the 489 carrier in a 71 dart drag car we have with a 605hp/665tq 500in. stroker and it lasted 3 seasons before breaking. We launch the car at 4500 with a trans brake and the car is a full caged drag car. The interior and everything are gutted for racing with a fiberglass fenders and hood. The car also has superstock springs and 10.5 slicks. All in the traction.....traction and hard launches breaks stuff. If you drive it normal and do an occasional burnout its hard to break hard parts like that.

 

[rumblefish360]

Yea my buddy has a 8 3/4 with the 489 carrier in a 71 dart drag car with a 605hp/665tq 500in. stroker and it lasted 3 seasons before breaking. He was launching the car at 4500 with a trans brake and the car was a full drag car. The interior and everything was gutted for racing with fiberglass fenders and hood. All in the traction.....traction and hard launches breaks stuff. If you drive it normal and do an occasional burnout its hard to break hard parts like that.

Thanks for that notation. I’m starting a project like that myself. A ‘71 Duster with a small block. The lightening project will start soon. I figure I’ll go as far as possible except windshield lexan. I’m not exactly sure how far I can go. Some things will have to wait. (I’m not the U.S. government with deep pockets that can just throw money at a problem.)
EZ things like fiberglass everywhere is one thing but the extra expense of tube K frame replacement will have to wait. I’d like to get out there before that. The car has a 8-3/4 w/4.88 gears, W5 headed destroker crank for 352 cubes. (Destroker assembly came in a package deal. Had to take it with a car purchase.)
So I figured I’d just use it.

 

[1967coronet440]

So I may have blown up my stock rear in my car last night. I'm going to take it apart to see exactly what broke but I'm thinking of upgrading anyway. (741 open diff with 2.94 gears) I was thinking about using a 489 case in an A-body width 8 3/4 housing as a "poor mans" narrowed rear to make more tire clearance. I didn't think they were much narrower but a local guy with a 67 Coronet said that's what he's running and fits a 315/60-15 with a mini tub and relocated springs.

My other option is possibly a Dana for strength. The problem is trying to find one that is already set up for a b-body , or getting one out of a truck then cutting it down and building it anyway or buying an S60 from Strange which are all expensive options. I do like the removable third member of the 8 3/4 and I don't think you can get a smaller gear than a 3.54 for a Dana. I want to stay between 2.94 and 3.23 ideally.

Or... for now I can just fix whatever is broken in my rear and maybe put a 489 case and posi unit in lol.

Basically is an 8 3/4 worth putting money into to hold up to high horsepower and torque levels (700-1000rwhp) or is a Dana required?

Dana

 

[91r/t]

Basically, if your looking for the response of what is stronger "apples to apples" than almost everyone (including myself) is going to tell you the Dana will beat it everytime. Now if your looking to stay in a budget, you can make something work with most parts laying around. The Mopar 8 3/4 will hold up unless you are literally pounding on it (slicks, trans brake).....then the old statement " you gotta pay to play" comes into effect and your gonna have to pony up for the bigger rear end.

 

[moparcrazy]

replacing my 8 3/4 Housing with this Fab 8.75 Housing & Running my 489 Center section

 

[YellowDodge67]

for that much h-p i would go with the 9" myself. i put a dana 60 in the hemi coronet and a 9" in the chevelle with much bigger power, both new from moser. definitely not cheap but the last one's i will have to buy.
-
i know i am not the sharpest knife in the drawer, but why are looking for those gears, "I want to stay between 2.94 and 3.23 ideally." with that much power. both mine are 3;90 or 3;91?? and o/d tranny's and i am barely over 2000rpm at 60mph. if i ordered again i might consider 3;70's at the least.

I could probably make 3.54s work, trying to gear it to trap around 150-155 in the quarter, on a 28in tire that'd be about 6500rpms with no converter slip. Maybe a 30in tire will be the trick.

Car is a turbo big block 67 Coronet wagon, street car weighing around 4000lbs. Car isn't that fast yet (about 500rwhp at the moment) but trying to plan for the end goal, especially on something this expensive.

 

[1967coronet440]

I could probably make 3.54s work, trying to gear it to trap around 150-155 in the quarter, on a 28in tire that'd be about 6500rpms with no converter slip. Maybe a 30in tire will be the trick.

Car is a turbo big block 67 Coronet wagon, street car weighing around 4000lbs. Car isn't that fast yet (about 500rwhp at the moment) but trying to plan for the end goal, especially on something this expensive.

Factory 440 block?

 

[YellowDodge67]

Factory 440 block?

Not for long lol

 

[1967coronet440]

Not for long lol

What block are you going with? My .02 just get the dana now you’ll never have to worry about it. If you build what you say you’re going to you are going to want to race it eventually, and an 8 3/4 won’t last.

 

[YellowDodge67]

What block are you going with? My .02 just get the dana now you’ll never have to worry about it. If you build what you say you’re going to you are going to want to race it eventually, and an 8 3/4 won’t last.

Haven't decided on a block yet. The one that's in it is still running so I'm replacing components as they fail. The whole project is gonna be a few years until it is in its final state, but when the parts fail and are subsequently replaced I'm trying to replace with the right stuff if possible.

 

[PurpleBeeper]

Well, for my 2-cents it is decision time. Do you want to cruise the car (8-3/4") or race the car (Dana/9"). As you've figured out, it is WAY cheaper to run the 8-3/4" and you have more gear choices.

On a related note, I had a 9-1/4" in a '77 Cordoba & after I put in a relatively mild 440 it broke into pieces... and that was when I was still breaking the motor in and hadn't even floored it once. I've been sort of scared of those rear ends ever since.

 

[1967coronet440]

Well, for my 2-cents it is decision time. Do you want to cruise the car (8-3/4") or race the car (Dana/9"). As you've figured out, it is WAY cheaper to run the 8-3/4" and you have more gear choices.

On a related note, I had a 9-1/4" in a '77 Cordoba & after I put in a relatively mild 440 it broke into pieces... and that was when I was still breaking the motor in and hadn't even floored it once. I've been sort of scared of those rear ends ever since.

Sounds like there was some sort of assembly failure, or maybe bogus parts used? 9 1/4 rearends are proven tough.

 

[747mopar]

I really think the answer is simple at least to me, if your putting stickies on it and launching it then Dana. Street tires only.. enjoy being able to swap gears in 30 minutes with an 8 3/4 but that's just me. I love being able to rebuild a pig with different gears then swap it quickly with little downtime.

 

[YellowDodge67]

I'm beginning to reconsider the 9in rear. I was trying to avoid a completely mixed up car (mopar engine, possibly a gm trans and a Ford rear) but having the removable center section and better gear selection is an advantage over the Dana, plus I have a Ford car with a 9in so being able to swap parts would be a bonus.

 

[mmissile]

If you want bullet-proof....your above combo seems to be working for lots of the faster guys. mopar engine, turbo400, 9-inch Ford.

 

[dvw]

155 mph in the 1/4? at what weight and power plant? Unless it's turboed you will need at the least a 4.10. The 8 3/4 should not be used in this application. I've run Junkyard Dana's narrowed with a spool, 35 spline axles, and street gears. In my car the first ring and pinion lasted 450 passes. I can tell you at 3350 lbs it takes every bit of 900+HP to go just under 150 mph.
Doug

 

[YellowDodge67]

155 mph in the 1/4? at what weight and power plant? Unless it's turboed you will need at the least a 4.10. The 8 3/4 should not be used in this application. I've run Junkyard Dana's narrowed with a spool, 35 spline axles, and street gears. In my car the first ring and pinion lasted 450 passes. I can tell you at 3350 lbs it takes every bit of 900+HP to go just under 150 mph.
Doug

It is turbo'd. That's a pretty good lifespan for a fairly basic rear combo you have