Will my 8-3/4 hold up behind a 4 speed?

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mshred

mshred

The Green Manalishi
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Hey guys,

I have been seriously considering going the 4 speed route in my scamp since i have all the parts for it, but now thinking of parts breaking im kind of worried. I have a 489 case 8-3/4 with the stock sure grip. i just bought moser custom alloy axles for it (30 spline) and plan on putting in 3.91 gears. My engine right now is just a mild 340 which i know will put me somewhere in the 13's. I know thats nothing to worry about right now, but in a couple years at most i would like to stroke my 340 out to 416. I know 4 speeds are harder on parts, and it would be nice to go for a dana right now to just be ready for any future power, but after buying the axles for my 8-3/4 (as well as new 11 inch drums) i dont want to change over to a Dana. I would just like to know how fast i can go with 4 speed smallblock car before i toast my 8-3/4 and have to upgrade to a dana 60....more power isnt planned until the future, but if i start to dip into the mid to high 12's and the rear can't handle it, i dont know if the 4 speed would be the best option for me in the long term with the parts i already have.

any help would be great guys
thanks
matthew
 
An 8 3/4" will take anything a smallblock can dish out. Ma Mopar didn't feel the need for a Dana 60 unless you had a Hemi 4 speed or a 440 6 pack 4 speed. I have never broken an 8 3/4" but I have broken Ford 9 inchers with the same car (505 big block 4 speed Charger R/T). Shame on me for listening to the people who told me I needed the POS Ford rear.
 
MSHRED, you should get your self some books and compare designs between manufacturers.
Some of the questions you ask sound like the byproduct of the advise a chevy guy gave you.
Just doesn't sound like a lot of faith i mopar to me.

If you simply look at factory SB & BB cars from chrysler you'd see that almost all high performance cars got the 8 3/4-[ex hemi 4spd=dana] and that was so the factory didn't have to worry about having to warranty anything.

You'll be fine.
 
I had a 69 Roadrunner (heavier than your car) with a 383/4 speed/8 3/4" years ago and I couldn't hurt it no matter how hard I tried.

Terry
 
3404spdvaliant said:
MSHRED, you should get your self some books and compare designs between manufacturers.
Some of the questions you ask sound like the byproduct of the advise a chevy guy gave you.
Just doesn't sound like a lot of faith i mopar to me.

If you simply look at factory SB & BB cars from chrysler you'd see that almost all high performance cars got the 8 3/4-[ex hemi 4spd=dana] and that was so the factory didn't have to worry about having to warranty anything.

You'll be fine.
Click to expand...

advise from chevy guys? im talking about Danas, not 12 bolts...the reason im asking is because i was sifting through a few threads in the 4 speed area and read of a member who ran 11.78 in a cuda and said that he broke his 8-3/4 and had to go dana- it was a 4 speed small block car...Im not a mechanic or a mopar expert, which is why i ask these questions...all my faith is in mopar, so for the second time in a little while please dont knock me anymore...just want advise, not your personal criticism on me...i cant even ask a simple question without being considered a brand xer...sheesh :angry7:...oh and by the way i was raised mopar- its in my blood..ill never buy, race, or modify anything else

So from the sounds of it i guess im fine then with my 8-3/4....thanks guys....quite a relief for me...its just something i thought of and wanted to make sure i would have the proper setup for...doesnt hurt to ask sometimes
 
mshred said:
advise from chevy guys? im talking about Danas, not 12 bolts...the reason im asking is because i was sifting through a few threads in the 4 speed area and read of a member who ran 11.78 in a cuda and said that he broke his 8-3/4 and had to go dana- it was a 4 speed small block car...Im not a mechanic or a mopar expert, which is why i ask these questions...all my faith is in mopar, so for the second time in a little while please dont knock me anymore...just want advise, not your personal criticism on me...i cant even ask a simple question without being considered a brand xer...sheesh :angry7:...oh and by the way i was raised mopar- its in my blood..ill never buy, race, or modify anything else

So from the sounds of it i guess im fine then with my 8-3/4....thanks guys....quite a relief for me...its just something i thought of and wanted to make sure i would have the proper setup for...doesnt hurt to ask sometimes
Click to expand...

YEA, AND DANA MADE REAR ENDS FOR MORE THEN JUST MOPARS.

I'M NOT INSULTING YOU FOR POSSIBLY GETTING ADVISE FROM A CHEVY GUY.
You had a tude in another thread if you don't remember....

Get a SENSE OF HUMOR and quit wearing your heart on your sleeve.
 
3404spdvaliant said:
YEA, AND DANA MADE REAR ENDS FOR MORE THEN JUST MOPARS.

I'M NOT INSULTING YOU FOR POSSIBLY GETTING ADVISE FROM A CHEVY GUY.
You had a tude in another thread if you don't remember....

Get a SENSE OF HUMOR and quit wearing your heart on your sleeve.
Click to expand...

Exactly what im talking about...why are you bringing up that other thread again when i asked you before to just lay it to rest...the chevy advice was for reasons that i already explained to you...i was aware that Dana made rears for more than mopars, but i was talkin about the 60's in the mopar context...i dont get advice from chevy guys and i do have a sense of humour, just not one towards people who get off making jokes that are kind of critical....If i didnt have faith in mopar, like you question yourself about, why the hell would i be building one then? If i didnt like them better than chevys, why would i be building one? These basic questions should answer your doubts....i appreciate the advice you give, because thats what i seek- when you throw in unnessacary comments judging me, my character, or what you think my character is, then i dont really find it humourous and could care less about the info you give....if you ever are going to give me informative replies (which are the ones i look for and appreciate) then please just refrain from dropping lines that you consider funny- they piss ME off...its too bad your sense of humour seems to be only pokes and insults at stupidity

thanks
 
Take it from someone who knows..if your going to be making any real power and going 4-speed get a dana, if you go automatic a beefed-up 8 3/4 will handle just about anything you can put in front of it..oh and a dana weights 50 lbs more also...
 
stroked 340 said:
Take it from someone who knows..if your going to be making any real power and going 4-speed get a dana, if you go automatic a beefed-up 8 3/4 will handle just about anything you can put in front of it..oh and a dana weights 50 lbs more also...
Click to expand...

thats what i thought, and thats what im trying to figure out...do you think that a mid 12 sec car with a 4 speed and small block will wreck an 8-3/4 with a stock sure grip and alloy axles (30 spline)? Im not going to be hitting those times soon, but i would like to be atleast in the mid 12's in a couple of years when i stroke my 340 and i just want to know what rear i should use
 
Mshred,there,s to kinds of pods 1 is sure-grip with clutches that can wear and are rebuildable 2 is a cone type that isn,t rebuildable.I had a cone type brake on me but it was my fault for putting a used pod.Who knows the pounding over the years it took or even what it was from??If you have a stock 340,sure-grip and the new axels,the only advise I could give is u-joints.When replacing your gears and axels you might as well replace them if you haven,t already.That way you know it,s all new,not sayin they won,t brake see,in your still wet behind the earsHaHA on launching and shifting!Practise is the main thing here til ya learn your car!Good luck with 4 speed!
 
hey scott, thanks for the info, and yes i am still wet behind the ears in the manual world lol...I will be upgrading to the larger u joint (think its 7620 or something if im im not mistaken)...unfortunatly i cant remember if i have the clutch type or cone type pod...and my pod is also a used one too, which like you said you never know what it went through before....but if im going to chance toasting the rearend by only going into the high 12's, then maybe the 8-3/4 isnt enough? dangit this isnt cool
 
mshred said:
Exactly what im talking about...why are you bringing up that other thread again when i asked you before to just lay it to rest...the chevy advice was for reasons that i already explained to you...i was aware that Dana made rears for more than mopars, but i was talkin about the 60's in the mopar context...i dont get advice from chevy guys and i do have a sense of humour, just not one towards people who get off making jokes that are kind of critical....If i didnt have faith in mopar, like you question yourself about, why the hell would i be building one then? If i didnt like them better than chevys, why would i be building one? These basic questions should answer your doubts....i appreciate the advice you give, because thats what i seek- when you throw in unnessacary comments judging me, my character, or what you think my character is, then i dont really find it humourous and could care less about the info you give....if you ever are going to give me informative replies (which are the ones i look for and appreciate) then please just refrain from dropping lines that you consider funny- they piss ME off...its too bad your sense of humour seems to be only pokes and insults at stupidity

thanks
Click to expand...


This is what I mean.
For someone ASKING you sure are picky about how it's given.
BTW I'm glad to piss you off, it's good for you.
 
If your stroking a 340 and putting it in to an a-body set up correctly,you'll be doing a LOT better then mid 12's...
 
hi, the 8 3/4 will live very well for what you have. there are things to consider with this rear end. the clutch pressure and disc will have a say on the life of gears. as long as you can spin the tires, should be no problems.
how ever, slicks and dead hooking will shorten gear life. as will lifting on the shifting. otherwise, it's strong enough. btw, get a 7290 or dana spider makes
a 1350 yoke for 8 3/4 rear end. I have a 1350 in rear and 7290 in front, both have held up very well.
 
3404spdvaliant said:
This is what I mean.
For someone ASKING you sure are picky about how it's given.
BTW I'm glad to piss you off, it's good for you.
Click to expand...

this is the last thing im going to write to you about this...On a forum, common courtesy is to RESPECT other members....when someone asks for advice, thats all they deserve- smart *** comments from people like you who cant get their arrogant head out of their *** arent nescessary...you remind me of young teenagers who love to talk **** on the internet in mom and dad's basement in their underwear (do you still live with your parents? lol)...I appreciate all the advice you have given so far in everything ive ever asked- not gonna lie you know what you are talkin about, and thats why i ask, so that knowledgable guys on the site like you can help out guys who need to learn some stuff, like me....Im not picky about how stuff is given, i just want the help and insight and thats it...not your personal bullshit criticism that you seem so good at throwing around in all your posts...some people put up with while others like me dont :thebirdm:...I have respect towards other people, which is something you obviously dont...you dont piss me off that much really, your more like an annoying typical internet **** talker who probably has no friends and is all smartass behind a screen:toothy10:
 
stroked 340 said:
If your stroking a 340 and putting it in to an a-body set up correctly,you'll be doing a LOT better then mid 12's...
Click to expand...

i sure hope so myself...im just being real conservative with numbers because even in the mid 12's im wondering how well my rear will hold

perfacar said:
hi, the 8 3/4 will live very well for what you have. there are things to consider with this rear end. the clutch pressure and disc will have a say on the life of gears. as long as you can spin the tires, should be no problems.
how ever, slicks and dead hooking will shorten gear life. as will lifting on the shifting. otherwise, it's strong enough. btw, get a 7290 or dana spider makes
a 1350 yoke for 8 3/4 rear end. I have a 1350 in rear and 7290 in front, both have held up very well.
Click to expand...

Thanks for the info... I was planning on ugrading to the bigger yokes, just got the name wrong...also, if i set up the 4 speed with a dual frictiong clutch, use the heavy duty yokes in the drivetrain, and run a good 12 inch drag radial how long before i can expect to have to upgrade to a better rear? (what et?) or do i not need to at all

thanks
 
hell..we all own mopars...now thats what I call a sense of humor.... your 8 3/4 will hold up well..I have owned several and only broke one...come to think of it..after the thrashing it took so often..I would have broken too...Good luck...
 
If you were running a 741 (small pinion shaft) rear with a 4 speed and sticky tires I would have serious concerns but not with the 742 or 489. My only advise is to go with a drive shaft loop, even if you are running it on the street mostly, just for piece of mind. They're a lot cheaper and easier to install than a Dana.

Terry
 
3404spdvaliant said:
This is what I mean.
For someone ASKING you sure are picky about how it's given.
BTW I'm glad to piss you off, it's good for you.
Click to expand...

Now it's my turn to do the same, you have been warned and now I'm getting several complaints on you....yet again!

Good by.
 
I have a 68 Barracuda 340, 4 speed so allow me to chime in.
In your situation I feel your 8 3/4 will be more than fine.

For me..... When you get to the point where you start launching at very high RPMs on slicks or running much faster it is time to go to a 60.

I had to change, yes HAD to change when 8,000rpm launches simply destroyed several 8 3/4s.
 
hey guys thanks for all the input...from consensus it seems i will be fine with an 8-3/4...i will have fat tires, but not slicks, and i definatly wont be shifting at 8 grand, nor do i see anything faster than mid 12's happening for atleast a couple of years...thanks for all the input fellas i appreciate it....guess im stil goin full speed ahead 4 speed style!
 
a friend of mine run in the 9 sec range with a big block stroker with a 8 3/4 an 513 gears no problem drive it like you stole it lol :toothy10::toothy10::toothy10: but with a spool
 
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