when to upgrade from an 8 3/4?

Posted By: dirt

when to upgrade from an 8 3/4? - 10/23/12 06:14 PM

I am working on a scamp for a friend and its going to be a race car. I am back halfing it probably with ladder bars. The motor is a 440 and used to run 11.60 in a stock weight 70 cuda. With an automatic. He asked what i thought about the8 3/4 he has. It needs narrowed yet but he allready has it. I thought it would be fine. But now he is talking about stroking the motor and getting better heads.
So at what point would you say the 8 3/4 needs changed out for a dana 60? If there is a point.
Thanks, kenny

Posted By: Cab_Burge

Re: when to upgrade from an 8 3/4? - 10/23/12 06:35 PM

There are several thnigs that come into play on how long the 8 3/4 will last,if it is a foot brake that is a one in the plus column, if a trans brake or stick shift car go straight to a Dana 60

If the car is over 3300 lbs with driver and is going to be able to run in the low 1.40 or 1.3 in the 60 ft. look hard at a Dana 60

If it is raced on bad tracks that the cars spins and then hooks look at using a Dana 60. If you decide to use the 8 3/4 back brace the housing, buy and install a steel cap for the drivers side of the third member, use the highest pinion tooth count you can live with, IE use a 4.30 instead of a 4.89 ratio. Buy a good set of race 35 spline axles and a 35 spline spool, if it is a street car and you absolutely must use a posi you should buy a good set of axles

If you use a "489" case throw the crush sleeve away and buy a pinion spacer to use to set the pinion depth and the pinion bearing preload

I used a 8 3/4 in my Duster with ladder bars without a back brace, bad decision on my part

I ended up bending the housing so bad it broke the welds off of the ladder bar mounts

During a run

The decision is your freinds to make, I bought a junkyard Dana 60 out of Ford 3/4 ton truck and had it narrowed

Look around, sometimes you can find a Dana 60 in a junkyard that they took in as a core that has a bad axle housing end that has the ring and pinion and sometimes a posi

I use to buy them for less than a hundred dollars and sell them for $150.00 to the other brand racers that had broken thier indestrutrable 12 bolts and 9 inch rar ends

Posted By: old_racer

Re: when to upgrade from an 8 3/4? - 10/23/12 06:37 PM

probably when you break it! that's what made me change mine, I'm sure my cars alot heavier tho.
Russ

Posted By: lowflyingdart

Re: when to upgrade from an 8 3/4? - 10/23/12 06:49 PM

It is cheaper to change now than to throw away money on an 8 3/4". Do not put your customer, his oppenets and the track officials in danger by putting an explosive combination together. At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes. In the long run it will be cheaper to runa a Dana 60.

Posted By: dogdays

Re: when to upgrade from an 8 3/4? - 10/23/12 07:03 PM

If no money has been spent on the 8 3/4 already, it's a no-brainer. Dana 60.
Doing all the stuff to the 8 3/4 will put the cost within a spit of the Dana, and the Dana won't break.
If he mods the 8 3/4 now, and has to build a Dana next year, will he be happy? I think not. Better to spend a little more money once than a little less money twice!
R.

Posted By: Guitar Jones

Re: when to upgrade from an 8 3/4? - 10/23/12 07:11 PM

Quote:

At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes.

Huh, I guess my 8 3/4 didn't get that memo.

Posted By: CrAzYMoPaRGuY

Re: when to upgrade from an 8 3/4? - 10/23/12 07:13 PM

Quote:

Quote:

At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes.

Huh, I guess my 8 3/4 didn't get that memo.

I was gonna say the same thing!!!!
My 63 Dodge had hundreds and hundreds of passes with a best of 11.63, never even looked INTO the diff!

Posted By: Cab_Burge

Re: when to upgrade from an 8 3/4? - 10/23/12 07:28 PM

Quote:

Quote:

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At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes.

Huh, I guess my 8 3/4 didn't get that memo.

I was gonna say the same thing!!!!
My 63 Dodge had hundreds and hundreds of passes with a best of 11.63, never even looked INTO the diff!

My 1963 Plymouth M.W. stocker got hundreds of runs on the original 4.56 OEM gears, they never broke

Most after market gears are not so good

OP, as already said, how lucky are you feeling?

Posted By: Thumperdart

Re: when to upgrade from an 8 3/4? - 10/23/12 07:36 PM

Quote:

Quote:

At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes.

Huh, I guess my 8 3/4 didn't get that memo.

Me neither............

A dana is definately something I`m considering in the future...........it`s only a matter of time.....

Posted By: mikeysmopars

Re: when to upgrade from an 8 3/4? - 10/23/12 08:24 PM

Same here... For now
Bottom Tens, 3200 lb car and no special mods, Just axles.
I can't badmouth an 8 3/4 but I do plan to replace it this winter with a Dana

Posted By: polyspheric

Re: when to upgrade from an 8 3/4? - 10/23/12 08:37 PM

It's only worth money to someone else while it's still in good shape.
After it breaks it costs you money either way.

Posted By: rickseeman

Re: when to upgrade from an 8 3/4? - 10/23/12 08:52 PM

Don't have him spend money narrowing a 8-3/4. That money will be better spent on a Dana.

Posted By: Twin Turbo Mower

Re: when to upgrade from an 8 3/4? - 10/23/12 09:06 PM

Got a doc diff dana in my dart, put it in last month. One less thing I have to worry about. I just wish it came with 3.23 gears like my 8 3/4 had. But the 3.54's will do.

Posted By: nssracer1

Re: when to upgrade from an 8 3/4? - 10/23/12 10:06 PM

I know Im crazy and its a NHRA Stocker that goes 9.80s over 400 passes and only broke it twice!!!!

Attached picture 7432482-DouglasDuellIndy.jpg

Posted By: gregsdart

Re: when to upgrade from an 8 3/4? - 10/23/12 10:28 PM

Do it now. Sell the 8 3/4 while it is in one piece and has value.

Posted By: deaks

Re: when to upgrade from an 8 3/4? - 10/23/12 10:39 PM

If you look in the parts section of this site, you will see someone has just posted a dana 60 with a spool and 35 spline shafts for $500 in NJ
Mick

Posted By: topside

Re: when to upgrade from an 8 3/4? - 10/23/12 10:40 PM

I gave the 8.75-vs-Dana60 choice a lot of thought on my wagon project, and the difference was only about $200 between narrowing & bracing an 8.75, axles, diff housing, caps, SureGrip, bearings, & gears vs a Dana with new good axles, SG, bearings, & gears. The car's just a footbrake BB deal, but with 3700-3800 lbs & slicks, I figure that's money well spent.
I have enough things to worry about already.
As a kind of bonus, that A-body rearend is pretty valuable, judging by the last time I needed one.

Posted By: SleeperBee

Re: when to upgrade from an 8 3/4? - 10/23/12 11:39 PM

Been thinking of this for a week! Stock weight 69 Super Bee automatic STREET car with 550 horse stroker being built now. My plan was to have the current 8 3/4 freshened with whatever it needed and buy axles. My resto buddy just picked up 2 69 B body Danas. He has been bugging me for the 3:55 8 3/4 for a year anyway. What will I spend on the 8 3/4 with parts and labor? I realize it's a vague question but is a Dana strong enough to change the fluid and take a chance? I've been thinking of a cost analysis trade of what I should be willing to pay him. No, we haven't talked money. Anyone?

Posted By: rickraw

Re: when to upgrade from an 8 3/4? - 10/23/12 11:47 PM

i would. pull the cover & check the ring & pinion.

Posted By: bdaz smblk

Re: when to upgrade from an 8 3/4? - 10/24/12 01:41 AM

I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

Posted By: 71yelladustr

Re: when to upgrade from an 8 3/4? - 10/24/12 02:07 AM

As mentioned above. Sell the 8 3/4 while it still is good. It will bring good money to offset your cost in going to a Dana. I used a 3/4 ton truck rear end that I narrowed and put car housing ends on it. Got some 35 spline axles w/ green bearings from Dr. Diff and all is well. Sold my 8 3/4 and when it was all said and done the Dana only cost me a little over $250 to put it in.

Posted By: mikeysmopars

Re: when to upgrade from an 8 3/4? - 10/24/12 04:51 AM

Quote:

I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

Posted By: Guitar Jones

Re: when to upgrade from an 8 3/4? - 10/24/12 12:23 PM

Honestly if I had it to do over I'd go with a Dana. I have a lot of money in my 8.75 with a spool, the MP aluminum case and pro gears that are only available in one ratio, a 4.86, so in hindsight if you are going to have to narrow it, buy axles and all that just get a Dana and be done with it.

Posted By: Thumperdart

Re: when to upgrade from an 8 3/4? - 10/24/12 02:43 PM

Quote:

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I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

I`ve seen your responces to this kind of post before and am curious if you`d shoot your bad-azz combo for us to see..............

Posted By: dragram440

Re: when to upgrade from an 8 3/4? - 10/24/12 02:46 PM

I have been running a 8 3/4 for the last three years at 3750 lbs and running 10.50's - 10.60's in my Charger and havent had any issuses yet. 1.48 best 60'. Probly only have just under under 100 passes.

Posted By: racerx

Re: when to upgrade from an 8 3/4? - 10/24/12 03:02 PM

I'v been 1.28's with mine on a 10.5w@3350

but if i was smart i'v would of did a Dana/9"

Posted By: 383man

Re: when to upgrade from an 8 3/4? - 10/24/12 09:34 PM

I use an 8-3/4 in my 63 and so far have run 10.70's and it still has stock axles in it. Its an auto car that goes just over 3700 lbs and other then the Detroit Locker it is all stock. Now I only race my car 2 or 3 times a year at the most and usually just a test & tune where I only make a few passes. I did not race it at all this year because of some personal problems. But I want to go to a Dana and would have if I had the money when I built my 493. If you have the cash go with the Dana as its good insurance. And if you blow the 8-3/4 you will be pulling the trans to fix the overrunning clutch (sprag). I am pushing my luck everytime I race my 63 and I know it but I can not afford a Dana right now or I would have one. Ron

Posted By: bdaz smblk

Re: when to upgrade from an 8 3/4? - 10/25/12 01:07 AM

Quote:

Quote:

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I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

I`ve seen your responces to this kind of post before and am curious if you`d shoot your bad-azz combo for us to see..............

What all would you like to know about it.The car has a nice w8 smallblock with a 727 true 29.5 x10.5 tire with exhaust full interior including a back seat all lights work could drive it on the street if i trusted all the idiot drivers now days (LOL).If u want to know more just say.Thanks Kenny

Posted By: actionange

Re: when to upgrade from an 8 3/4? - 10/25/12 01:17 AM

3750 lbs race ready with driver. Mark Williams spool and axles. Housing has a back brace.
Best of 10.18@ 133.04
Only broke 1 ring gear in 8 years of racing

Attached picture 7434013-resizedLVD.jpg

Posted By: actionange

Re: when to upgrade from an 8 3/4? - 10/25/12 01:23 AM

Here's the broken ring gear. Manufacturer unknown- bought center used. Upgraded to Mark Williams spool and axles after this with Richmond gears.

Attached picture 7434021-resizedrearchuck.jpg

Attached picture 7434021-resizedrearchuck.jpg

Posted By: kissmyaspen

Re: when to upgrade from an 8 3/4? - 10/25/12 01:27 AM

Quote:

Quote:

At 11.90 ETs an 8 3/4" ring and pinion needs to be replaced every 100 passes.

Huh, I guess my 8 3/4 didn't get that memo.

my 8 1/4 should have blown up many many years ago.. cuz im 3600lb running 12.30's...

but if your building the car now i would go 9" or dana

Posted By: Thumperdart

Re: when to upgrade from an 8 3/4? - 10/25/12 02:31 AM

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Quote:

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I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

I`ve seen your responces to this kind of post before and am curious if you`d shoot your bad-azz combo for us to see..............

What all would you like to know about it.The car has a nice w8 smallblock with a 727 true 29.5 x10.5 tire with exhaust full interior including a back seat all lights work could drive it on the street if i trusted all the idiot drivers now days (LOL).If u want to know more just say.Thanks Kenny

I`ll say..........NICE is an understatement..........9.0`s, small block n/a, 3200lbs..........that doesn`t happen everyday.........

Posted By: bdaz smblk

Re: when to upgrade from an 8 3/4? - 10/25/12 02:39 AM

Quote:

Quote:

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I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

I`ve seen your responces to this kind of post before and am curious if you`d shoot your bad-azz combo for us to see..............

What all would you like to know about it.The car has a nice w8 smallblock with a 727 true 29.5 x10.5 tire with exhaust full interior including a back seat all lights work could drive it on the street if i trusted all the idiot drivers now days (LOL).If u want to know more just say.Thanks Kenny

I`ll say..........NICE is an understatement..........9.0`s, small block n/a, 3200lbs..........that doesn`t happen everyday.........

Thanks your car runs dang good too.I didn't even have the car out this year but hope to lighten the car up and be racing again sometime.If i wasn't broke as a dang on joke i would have a chrome moly cage in this car and save alot of weight.LOL

Posted By: cudaman1969

Re: when to upgrade from an 8 3/4? - 10/25/12 03:05 AM

Quote:

I am working on a scamp for a friend and its going to be a race car. I am back halfing it probably with ladder bars. The motor is a 440 and used to run 11.60 in a stock weight 70 cuda. With an automatic. He asked what i thought about the8 3/4 he has. It needs narrowed yet but he allready has it. I thought it would be fine. But now he is talking about stroking the motor and getting better heads.
So at what point would you say the 8 3/4 needs changed out for a dana 60? If there is a point.
Thanks, kenny [/quote

Right after you brake the 8 3/4 .Put a dana in and forget it for years

Posted By: mopar65

Re: when to upgrade from an 8 3/4? - 10/25/12 04:00 AM

Quote:

As mentioned above. Sell the 8 3/4 while it still is good. It will bring good money to offset your cost in going to a Dana. I used a 3/4 ton truck rear end that I narrowed and put car housing ends on it. Got some 35 spline axles w/ green bearings from Dr. Diff and all is well. Sold my 8 3/4 and when it was all said and done the Dana only cost me a little over $250 to put it in.

hey when are you going to start on my Dana??lol hey i am ether going to the track this Friday or Saturday if it rains. want to go?? Mopar65

Posted By: 71yelladustr

Re: when to upgrade from an 8 3/4? - 10/27/12 12:09 AM

Thanks for the invite Bobby. Cant go this weekend. Got to finish putting Dewaynes 496 back together for his Challenger. As for the Dana, JP up at Skyline welding cut down the tubes and made a jig to welded my ends on my rearend. I just ordered some axles from Dr. Diff and cut them with a chopsaw and slid them in. Nothing to it. Good luck at the track this weekend. Maybe next sping I'll take my junk up there and see what I can tear up.

Posted By: Thumperdart

Re: when to upgrade from an 8 3/4? - 10/27/12 01:33 AM

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I've been 9.0's 150 at 3,200 with a 8 3/4 with 1.20 couple 60 ft.

I`ve seen your responces to this kind of post before and am curious if you`d shoot your bad-azz combo for us to see..............

What all would you like to know about it.The car has a nice w8 smallblock with a 727 true 29.5 x10.5 tire with exhaust full interior including a back seat all lights work could drive it on the street if i trusted all the idiot drivers now days (LOL).If u want to know more just say.Thanks Kenny

I`ll say..........NICE is an understatement..........9.0`s, small block n/a, 3200lbs..........that doesn`t happen everyday.........

Thanks your car runs dang good too.I didn't even have the car out this year but hope to lighten the car up and be racing again sometime.If i wasn't broke as a dang on joke i would have a chrome moly cage in this car and save alot of weight.LOL

I`m more broke than I`ve been in years but nothing lasts forever and I`m kickin butt in college and if I can make it happen, I`ll be a smog guy/tech and have mad skills in an area that`s here to stay...........emissions baby. I`ve tried to get hot rod jobs here and there and feel like I`m kissing ass and no one has the nuts to respond back so that`s over now. Smog techs make top dollar, don`t work too hard and have great hours that I will controll. I too would love to lighten up my heap and will soon enuff a little bit at a time. Good luck to ya! peace.