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Re: 8 3/4 strength poll!!
[Re: RUNCHARGER]
#110702
08/26/08 10:43 PM
08/26/08 10:43 PM
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Joined: Jan 2003
Posts: 6,497
N.E. Ohio
KillerBee
master
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master
Joined: Jan 2003
Posts: 6,497
N.E. Ohio
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My all steel 440 Sixpack powered 4 speed Challenger broke it's stock axle the VERY first time I took it to the track with ET Street tires.  I tried to launch the car extremely hard when the axle broke. I replaced the axles with Moser ones and have ran the car a few more time at the track since without breaking anything but I have been doing much easier launches. My car has run a best of 11.80. I will definitely have a Dana under the car before any super hard launches again. I think an 8 3/4 could be built(modified) to survive behind a 500-600hp automatic car(no trans brake) but NOT behind a heavy, 4 speed, big block car with sticky tires running at the track on a regular basis 
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Re: 8 3/4 strength poll!!
[Re: 383man]
#110705
08/27/08 03:45 AM
08/27/08 03:45 AM
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Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
jyrki
master
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master
Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
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Foot brake street cars, 10+ years of driving street & strip, all 8 3/4's with aftermarket axles, stock sure grips (both styles), most runs during this period in the low 10's with weights from 3240 to 3510, best ET's in the 9.4's with 1.39 60 ft times. Three cars, four rebuilds over all. One total gear breakage, others rebuilds were because of wear. At some point we backbraced them, and in one rear added cap preload bolts. Anyway, in my opinion they were pretty much trouble free. If you are starting with nothing and building a powerful car, I would go with something else. We chose Dana because it's less money, but now I wish I had gone with the 9". Lighter, easier to work on and everyone has parts for one.
Plynouth VIP '67 TT IC EFI
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Re: 8 3/4 strength poll!!
[Re: Neil]
#110708
08/27/08 10:27 AM
08/27/08 10:27 AM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
How does one put down 1800 hp with an open rear end in a fuel car? All the videos and pictures that show the 60's and 70's cars smoking the tires down the track show both tires ablaze. 
Very narrow solid mounted rear goes a long way towards equaling traction. In a street car, you can preload the right rear with an air shock and accomplish the same thing.
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Re: 8 3/4 strength poll!!
[Re: JohnRR]
#110710
08/27/08 01:05 PM
08/27/08 01:05 PM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
Quote:
You guys need to brush up on your history a bit. The 8 3/4 was the first rear in the 5's...a mainstay in the Top Fuel cars right up to the early 70's. Keep in mind that spools didn't become popular until '72 or so, and up to that point it was pretty evenly split between open and sure grip diffs in the Fuelers. According to the spec sheet on Garlits first R/E car, it was rolling on 4:10 gears and stock Chrysler spiders.
Top fuel cars were running in the 5's in the early 70's ???
Ok guys sell your dana 60's and the rest of your safety equipment , the early pioneers of the sport did just fine without it ... it's a MONEY GRAB
edit .... oops , now i did it i questioned an icon of mopardom 
Go ahead and question me! Tommy Ivo ran the first 5 (426/8 3/4) but it was done at a match race and so it didn't count as official.
First official 5 was a 5.97 by Mike Snively in the Diamond Jim Annin T/Fueler (426/Dana). This was at the 72 Supernationals at Ontario. Same event, same day, Don Moody clocked at 5.91 (392/8 3/4) in the Walton Cerny Moody car.
There was alot of speculation at the time about hot clocks, but at the beginning of the 73 season 5's became common. I believe Garlits ran a 5.78 or so at Indy that year...also spit out a 250 that stood for some time.
At about this level, the 8 3/4 was starting to reach its breaking point. There was a guy that went by the name of Major Cooksey from Florida who was known as The Man when it came to T/F 8 3/4's...I believe there was an artical in Car Craft around 1972 that outlined his prep steps.
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Re: 8 3/4 strength poll!!
[Re: Qbird]
#110711
08/27/08 01:38 PM
08/27/08 01:38 PM
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Joined: Jan 2003
Posts: 17,841
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,841
S.E. Michigan
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Not to interrupt the John and Tony show....but I run a Dana for 1 reason: I don't have a trailer. The strip is an hour and a half drive...if the car ever broke there, the tow bill would probably cost the same as the axle, so I just did the axle and got it over with. That said, the 8 3/4 held up great for me and took me from 13 flat to low 11s without any issues (other than paranoia setting in).
Rich H.
Esse Quam Videri
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Re: 8 3/4 strength poll!!
[Re: hemiluver]
#110712
08/27/08 01:39 PM
08/27/08 01:39 PM
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Joined: Mar 2008
Posts: 571
Western NC
68Bullit
mopar
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mopar
Joined: Mar 2008
Posts: 571
Western NC
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No mention here of any types of 8.75 cases, such as the 489 case. Is it really stronger? Are some of the more extreme horsepower setups allowing the rearend to hold up because of a stronger 8.75 case?
Last edited by 68Bullit; 08/27/08 01:43 PM.
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Re: 8 3/4 strength poll!!
[Re: ZIPPY]
#110713
08/27/08 01:54 PM
08/27/08 01:54 PM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
Not to interrupt the John and Tony show....but
I run a Dana for 1 reason: I don't have a trailer.
The strip is an hour and a half drive...if the car ever broke there, the tow bill would probably cost the same as the axle, so I just did the axle and got it over with.
That said, the 8 3/4 held up great for me and took me from 13 flat to low 11s without any issues (other than paranoia setting in).
I've got nothing against the Dana...I've used plenty of them over the years, and if I was building a heavy stick car, that would be my first choice.
The discussion here was about the ultimate strength of the 8 3/4 and all I did was point out the most extreme applications for the rear.
I am currently building a twin engine Fuel Altered for myself, and decided to go with an 8 3/4 for a few reasons. With the direct drive/crowerglide combination in this particular car, I don't see shock loading to be a major issue. Also, with all the torque on tap, I don't see this car ever actually hooking up until waaaaay down the track.
Since this thing has two engines, I'm looking to save weight any place I can, and the 60 pound difference will help keep me under my target 2000 pound weight.
If I find that I can't get more than two or three passes out of the 8 3/4 I'll swap over to a Dana. Axles, brakes and whatnot will all swap over, so it's not that big of a deal to me. I can always use the 8 3/4 stuff in one of my street cars, so there's no waste.
Before anybody asks the obvious question..I have absolutely nothing against the 9 inch Ford...other than this car is going to be in MY garage. If I own it, it's going to be 100% Mopar.
Last edited by Qbird; 08/27/08 02:04 PM.
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Re: 8 3/4 strength poll!!
[Re: 68Bullit]
#110714
08/27/08 01:58 PM
08/27/08 01:58 PM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
No mention here of any types of 8.75 cases, such as the 489 case. Is it really stronger? Are some of the more extreme horsepower setups allowing the rearend to hold up because of a stronger 8.75 case?
It's not the case that is stronger, it's the style of pinion gear that's used in the various cases.
489 strongest, 742 next best and 741 is pretty much passenger car only.
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Re: 8 3/4 strength poll!!
[Re: hemiluver]
#110715
08/27/08 02:01 PM
08/27/08 02:01 PM
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Joined: Oct 2003
Posts: 4,009
South Park, Pa.
68LAR
master
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master
Joined: Oct 2003
Posts: 4,009
South Park, Pa.
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If you want real life experience and input, here it is. My car weighs 3726 with a half tank of gas. Add another 200+ for me. 4 speed launching at 4K and 3900+ pounds. The 8 3/4 lasted many years until I started going faster. Once I hit the low 12's is when things started to come apart. U joints, the twisting axles, then bearing retainers, then twisting housings even after back bracing. I've had my dana in now for 3 years going on 4 and have not had one breakage. I could have saved a lot of money if I would have put the Dana in years ago, but I was a bull head. An 8 3/4 will last a lot longer with a light car and an automatic. A heavy car,a stick and slicks and you are living on borrowed time.
4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
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Re: 8 3/4 strength poll!!
[Re: 68LAR]
#110716
08/27/08 03:41 PM
08/27/08 03:41 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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68LAR: I think that is the most factual post on here regarding the Poster's original question. An 8 3/4 can be okay but I think 68LAR's experience mimic what most have experienced. I've been lucky a few times finding twisted axles and other problems with 8 3/4's before they failed big time. That's in automatic E and B-bodies that were streetable, mostly low 12 cars.
Sheldon
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Re: 8 3/4 strength poll!!
[Re: Qbird]
#110717
08/27/08 04:05 PM
08/27/08 04:05 PM
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Joined: Jan 2003
Posts: 74,978
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 74,978
U.S.S.A.
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Quote:
Quote:
Quote:
You guys need to brush up on your history a bit. The 8 3/4 was the first rear in the 5's...a mainstay in the Top Fuel cars right up to the early 70's. Keep in mind that spools didn't become popular until '72 or so, and up to that point it was pretty evenly split between open and sure grip diffs in the Fuelers. According to the spec sheet on Garlits first R/E car, it was rolling on 4:10 gears and stock Chrysler spiders.
Top fuel cars were running in the 5's in the early 70's ???
Ok guys sell your dana 60's and the rest of your safety equipment , the early pioneers of the sport did just fine without it ... it's a MONEY GRAB
edit .... oops , now i did it i questioned an icon of mopardom
Go ahead and question me! Tommy Ivo ran the first 5 (426/8 3/4) but it was done at a match race and so it didn't count as official.
First official 5 was a 5.97 by Mike Snively in the Diamond Jim Annin T/Fueler (426/Dana). This was at the 72 Supernationals at Ontario. Same event, same day, Don Moody clocked at 5.91 (392/8 3/4) in the Walton Cerny Moody car.
There was alot of speculation at the time about hot clocks, but at the beginning of the 73 season 5's became common. I believe Garlits ran a 5.78 or so at Indy that year...also spit out a 250 that stood for some time.
At about this level, the 8 3/4 was starting to reach its breaking point. There was a guy that went by the name of Major Cooksey from Florida who was known as The Man when it came to T/F 8 3/4's...I believe there was an artical in Car Craft around 1972 that outlined his prep steps.
thanks tony , stupid question though , how HEAVY were those cars ??? did they have TRANSBRAKES ??
as far as strength i feel the nod goes to the 742 over a 489 even with a solid spacer ... but that is just my opinion ...
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Re: 8 3/4 strength poll!!
[Re: Qbird]
#110718
08/27/08 04:05 PM
08/27/08 04:05 PM
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Joined: Oct 2004
Posts: 16,477
Canada
CrAzYMoPaRGuY
I Live Here
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I Live Here
Joined: Oct 2004
Posts: 16,477
Canada
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Quote:
I've got nothing against the Dana...I've used plenty of them over the years, and if I was building a heavy stick car, that would be my first choice.
The discussion here was about the ultimate strength of the 8 3/4 and all I did was point out the most extreme applications for the rear.
I am currently building a twin engine Fuel Altered for myself, and decided to go with an 8 3/4 for a few reasons. With the direct drive/crowerglide combination in this particular car, I don't see shock loading to be a major issue. Also, with all the torque on tap, I don't see this car ever actually hooking up until waaaaay down the track.
Since this thing has two engines, I'm looking to save weight any place I can, and the 60 pound difference will help keep me under my target 2000 pound weight.
If I find that I can't get more than two or three passes out of the 8 3/4 I'll swap over to a Dana. Axles, brakes and whatnot will all swap over, so it's not that big of a deal to me. I can always use the 8 3/4 stuff in one of my street cars, so there's no waste.
Before anybody asks the obvious question..I have absolutely nothing against the 9 inch Ford...other than this car is going to be in MY garage. If I own it, it's going to be 100% Mopar.
Haha!
MY kinda guy!
I have nothing against the Dana rears either, great piece. I'll repeat that I started with a blank piece of paper with my Coupe, and money was no object to me, I went with an 8 3/4 rear too.
CrAzYMoPaRGuY
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Re: 8 3/4 strength poll!!
[Re: JohnRR]
#110719
08/27/08 05:25 PM
08/27/08 05:25 PM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
Quote:
Quote:
Quote:
You guys need to brush up on your history a bit. The 8 3/4 was the first rear in the 5's...a mainstay in the Top Fuel cars right up to the early 70's. Keep in mind that spools didn't become popular until '72 or so, and up to that point it was pretty evenly split between open and sure grip diffs in the Fuelers. According to the spec sheet on Garlits first R/E car, it was rolling on 4:10 gears and stock Chrysler spiders.
Top fuel cars were running in the 5's in the early 70's ???
Ok guys sell your dana 60's and the rest of your safety equipment , the early pioneers of the sport did just fine without it ... it's a MONEY GRAB
edit .... oops , now i did it i questioned an icon of mopardom
Go ahead and question me! Tommy Ivo ran the first 5 (426/8 3/4) but it was done at a match race and so it didn't count as official.
First official 5 was a 5.97 by Mike Snively in the Diamond Jim Annin T/Fueler (426/Dana). This was at the 72 Supernationals at Ontario. Same event, same day, Don Moody clocked at 5.91 (392/8 3/4) in the Walton Cerny Moody car.
There was alot of speculation at the time about hot clocks, but at the beginning of the 73 season 5's became common. I believe Garlits ran a 5.78 or so at Indy that year...also spit out a 250 that stood for some time.
At about this level, the 8 3/4 was starting to reach its breaking point. There was a guy that went by the name of Major Cooksey from Florida who was known as The Man when it came to T/F 8 3/4's...I believe there was an artical in Car Craft around 1972 that outlined his prep steps.
thanks tony , stupid question though , how HEAVY were those cars ??? did they have TRANSBRAKES ??
as far as strength i feel the nod goes to the 742 over a 489 even with a solid spacer ... but that is just my opinion ...
The typical T/F car of the era probably hit the starting line at about 1600 pounds (Fuel, oil, driver). Prudhomme fielded a car in 72 called The Yellow Feather, and if I remeber correctly, it was just a hair under 1200 pounds dry.
No transbrakes in those days. At the time the pack was pretty evenly split between pedal clutches and Crowerglides. Funnies of the era weighed about 300 pounds more and were using 2 speed transmissions. Diggers were still high gear only.
You've got me curious. Why would you choose the 742 over the 489. I've been gathering parts for this project and have 3 489 cases lined up for it. Think I'm going the wrong way?
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Re: 8 3/4 strength poll!!
[Re: Qbird]
#110720
08/27/08 06:43 PM
08/27/08 06:43 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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The 489 is fine, just use a solid spacer rather than the factory crush sleeve.
Sheldon
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Re: 8 3/4 strength poll!!
#110721
08/27/08 08:06 PM
08/27/08 08:06 PM
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Joined: Aug 2006
Posts: 540
murfreesboro, TN
Qbird
mopar
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mopar
Joined: Aug 2006
Posts: 540
murfreesboro, TN
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Quote:
The 489 is fine, just use a solid spacer rather than the factory crush sleeve.
Sheldon
Yeah, that's what I thought.
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Ron
