8 3/4 Limit?

[5.7 hemi]

Same here. That included new 35 spline axles with green bearings.

 

[5.7 hemi]

https://www.forbbodiesonly.com/moparforum/threads/shorten-dana-60.144581/

 

[Cranky]

I'll have a 55" 60 for sale before long. It's truck housing that's cut down. Only down side to a truck housing is it has no provision for a pinion snubber....

 

[5.7 hemi]

Dr. Diff at one time made stand offs to weld on the 60 housing so a pinion snubber could be used.

 

[Dodge 330]

I'll have a 55" 60 for sale before long. It's truck housing that's cut down. Only down side to a truck housing is it has no provision for a pinion snubber....

I use Cal-Tracs. No need for a snubber.

 

[69roadr]

I've got 500 horsepower in my 383 Street driven. Would be skeptical about taking it out to the track

 

[Cranky]

Dr. Diff at one time made stand offs to weld on the 60 housing so a pinion snubber could be used.

Not sure if he still offers that. The housing is a casting so it's a bit more difficult to weld to. Ya just can't (shouldn't?) go at it with the average home MIG machine but someone with a bit more knowledge can usually TIG or STICK it with no problem.

 

[5.7 hemi]

I don’t see them on his website anymore, but a guy over on FABO got some and welded them on. Not sure when this happened.

 

[6PKRTSE]

I used to have a 69' Pro Street Charger that I ran 32" X 14" slicks or 31.5" X 16.5" Hoosier street tires. The car ran 10.40's on one kit, never sprayed the second kit at the track, only on the street. This was with all stock 8-3/4 Chrysler parts including axles. Eventually, I sold the car & the guy I sold it to drove it another 5 years or so on the street until he sold it. Yes, I was probably maxed out at what the 8-3/4 was taking but never hurt anything.

 

[Cranky]

I used to have a 69' Pro Street Charger that I ran 32" X 14" slicks or 31.5" X 16.5" Hoosier street tires. The car ran 10.40's on one kit, never sprayed the second kit at the track, only on the street. This was with all stock 8-3/4 Chrysler parts including axles. Eventually, I sold the car & the guy I sold it to drove it another 5 years or so on the street until he sold it. Yes, I was probably maxed out at what the 8-3/4 was taking but never hurt anything.

Yup, a lot of people run them to their limits but when they finally give up, it can be catastrophic. Many times when a rear end gives up the ghost, it'll lock up and when that happens, you're just along for the ride. It's bad enough when an axle breaks but if the gears etc crater and things lock up and you're going fast enough, a totaled out car or worse can result so why play that game?

 

[gtxracer]

I'll have a 55" 60 for sale before long. It's truck housing that's cut down. Only down side to a truck housing is it has no provision for a pinion snubber....

Cranky, I also use Cal Tracs on my GTX and no snubber. If the Dana 60 you have is for sale, PM me with some info and maybe I will switch. Thanks... Bob

 

[67 coronet]

the key here is track vs street use. the traction at the track is so much more of a hit on the rear that there is no comparison. if used as a drag car, you have to switch to the 60.

 

[Cranky]

Cranky, I also use Cal Tracs on my GTX and no snubber. If the Dana 60 you have is for sale, PM me with some info and maybe I will switch. Thanks... Bob

PM sent....

the key here is track vs street use. the traction at the track is so much more of a hit on the rear that there is no comparison. if used as a drag car, you have to switch to the 60.

It's not all that hard to get good traction on the street too but yeah, drag cars usually get a lot more abuse (unless you are me ) than street cars...

 

[1967coronet440]

Strange Black Friday sale, the time is now.

 

[Budnicks]

I org. had a 8.750" various 489 & 742 cases,
in my 1st 23 altered

edited; to correct a couple mistakes
I was going for light as possible (car was 1800#'s)
easily serviceable drop out plug/gears
it had Lenco drivetrain parts, full floating axles,
billet caps & ARP (?) studs
it was only 38" long or so
Astroloy, nickel based metal (spelling) for shafting material
(for my axels, they were the parts that suffered the most)
they used that stuff on the space shuttles

it was solid mounted in the car too
went 6.90's @ 190+ as much as 217mph
did it for a couple years,
slowest it ever was, was a 8.90 comp car @ 145+
injected SBC 301 ci 6#'s per/ci

I just checked & updated the bearings & gears regularly
I had quite a few gear selections too, depending on track or class
3.90:1, 4.10:1, 4.30:1, 4.56:1 & 4.88:1 (Lenco & Richmond IIRC)
depending on what track or engines, 14 x 32" & 15 x 33" Good Years

I had a blown-injected alky SBC 800hp
then appr. 1500-1600hp BBC blown
& or just alky injected 800+hp BBC

& later an old T/A 526ci Milodon Mastodon Alum. Hemi Blown-injected
combo in the car
I never broke a gear or the housing, ever
but it was trussed up
& it had pro-gears too
full floating axles ends,
spool in 30 spline & later 35 spline later 10 spline on the outer
so if you broke an axle the tires stayed on the car
(they don't make pro-gears for a 8.750" anymore, quit more than a decade ago)
I did break an axle, 30 or 35(?)-10 spline Lenco axles,
drag-racing specific hardened axles

It was too cost prohibitive, after a while,
had to have parts made or machined from billet

they quit making pro-gears too,
pretty much made up my mind for me
I got about 100 passes out of them max.
I usually didn't put 100 passes on any of them...

I ended up with a 8.875" 12 bolt based GM Lenco setup later
not a cheap deal either, broke an axle once on that too
it was only marginally heavier like 25#'s

my newer 27 Altered
(I ran for a couple seasons, super eliminator S/E 7.90 class)
it had a Dana 60, tried several different gears ratios
the car was marginally slower, heavier by another 25#'s or so,
like 50#'s more than the org. narrowed trussed 8.750" was
but it's also heavier in the right place

I could take ballast out of the car
no doubt it was stronger it has a bigger 9.250" ring gear
& better pinion location, less power robbing
It was right under my back, you laid/sat over the rear-end housing
you have to be able to trust it won't grenade (blow up)
take off your family jewels (ouch) or back/leg etc.
especially at the speeds & ET's I was going

it was pricey even back then,
even doing most the work myself
or Jim Davis/Pete Kaiser, help tuning & setting up
& Don Tourte chassis builder/pro-fabricator aiding me

they 8.750" can take a lot more than people think
especially with all the right parts
alum 742 carrier, trussed, billet caps, quality hardware, studs
quality bearings, aftermarket &/or floater axles, spool etc.

I had a stock housing with trusses
in my old silver 68 RR 3520#'s, form about 10 years ago
went best of 'on the juice' 300 shot 8.58 @ 156
ran in the high 8's @ over 150 on the juice regularly
on 305/60/15 M/T drag radials & CalTracs
had over 100 passes @ the track, on it
it'd run 9.77 @ 135 with out N2O, ran in the 9.90's regularly
never broke it, it was street driven regularly too
before that ran in the 10's @ 130's for a couple years too

it's still "allegedly" street driven around Sacramento area
same set up I used, may have been freshened up by now

I'm pretty sure it was at it's limits too
maybe even on borrowed time

If I was to build another car like that today
I'd either just buy a S-60
or build one out of a Dana-60 Truck axle, for 1/2 that price

 

[beanhead]

I org. had a 8.750" various 489 & 742 cases,
in my 1st 23 altered
View attachment 681337

I was going for light as possible (car was 1800#'s)
easily serviceable drop out plug/gears
it had Lenco drivetrain parts, full floating axles,
it was only 38" long or so
astrology, nickel based metal (spelling) shafting material
(for my axels, they were the parts that suffered the most)
they used that stuff on the space shuttles

it was solid mounted in the car too
went 6.90's @ 190+ as much as 217mph
did it for a couple years,
slowest it ever was, was a 8.90 comp car @ 145+
injected SBC 301 ci 6#'s per/ci

I just checked & updated the bearings & gears regularly
I had quite a few gear selections too, depending on track or class
3.90:1, 4.10:1, 4.30:1, 4.56:1 & 4.88:1 (Lenco & Richmond IIRC)
depending on what track or engines, 14 x 32" & 15 x 33" Good Years

I had a blown-injected alky SBC 800hp
then appr. 1500-1600hp BBC blown
& or just alky injected 800+hp BBC
View attachment 681339

& later an old T/A 526ci Milodon Mastodon Alum. Hemi Blown-injected
combo in the car
I never broke a gear or the housing, ever
but it was trussed up
& it had pro-gears too
full floating axles ends,
spool in 30 spline & later 35 spline later 10 spline on the outer
so if you broke an axle the tires stayed on the car
(they don't make pro-gears for a 8.750" anymore, quit more than a decade ago)
I did break an axle, 30 or 35(?)-10 spline Lenco axles,
drag-racing specific hardened axles

It was too cost prohibitive, after a while,
had to have parts made or machined from billet

they quit making pro-gears too,
pretty much made up my mind for me
I got about 100 passes out of them max.
I usually didn't put 100 passes on any of them...

I ended up with a 8.875" 12 bolt based GM Lenco setup later
not a cheap deal either, broke an axle once on that too
it was only marginally heavier like 25#'s

my newer 27 Altered
(I ran for a couple seasons, super eliminator S/E 7.90 class)
it had a Dana 60, tried several different gears ratios
the car was marginally slower, heavier by another 25#'s or so,
like 50#'s more than the org. narrowed trussed 8.750" was
but it's also heavier in the right place

I could take ballast out of the car
no doubt it was stronger it has a bigger 9.250" ring gear
& better pinion location, less power robbing
It was right under my back, you laid/sat over the rear-end housing
you have to be able to trust it won't grenade (blow up)
take of you family jewels or back/leg etc.
especially at the speeds & ET's I was going

it was pricey even back then,
even doing most the work myself
or Jim Davis/Pete Kaiser, help tuning & setting up
& Don Tourte chassis builder/pro-fabricator aiding me

they 8.750" can take a lot more than people think
especially with all the right parts
alum 742 carrier, trussed
aftermarket &/or floater axles

I had a stock housing with trusses
in my old silver 68 RR 3520#'s
went best of 'on the juice' 300 shot 8.58 @ 156
ran in the high 8's @ over 150 on the juice
on 305/60/15 M/T drag radials & CalTracs
had over 100 passes @ the track, on it
it'd run 9.77 @ 135 with out N2O, ran in the 9.90's regularly
never broke it, it was street driven regularly too

it's still "allegedly" street driven around Sacramento area

I'm pretty sure it was at it's limits too
maybe even on borrowed time

If I was to build another car like that today
I'd either just buy a S-60
or build one out of a Dana-60 Truck axle, for 1/2 that price

View attachment 681342

 

[beanhead]

Like Budnicks says, it's all about the parts..a stock Dana is obviously gonna take more abuse than a stock 8-3/4 but they've held their own at the track. 700hp with hard hitting traction I'd shell out for the big boy...street tires and a 500hp big block the 8-3/4 is fine (unless you're me and get two bad clutch diffs in a row lol...true-trac solved that problem!) In the OPs case, with that extra bump from the nitrous by the time you build that 8-3/4 up enough to handle it, the cost of going to the Dana would be too close to chance it..

 

[Cranky]

Bud, you said a mouthful there lol. And we were starting to have some trouble getting pro gears in the ratios we wanted for the 8 3/4 all the way back in the early 80's! And you're right about them not lasting all that long however I did get 300+ passes on a set of 4.88's PG's in a 60 but wasn't running nearly as fast as you were. And it was the stock gears that we were breaking with the 8 3/4 especially launching at 6k. Even the stock axles were holding up ok but they did get looked at often.

 

[66Satellite47]

Plain & simple, a Dana 60 is heavier than an 8 3/4". If you go Dana you never go back. You can make an 8 3/4 hold up to lots of power, but it takes lots of parts & careful monitoring. As Cranky indicated, gear selection with an 8 3/4 is critical. Example, 4.89 gear tooth in 8 3/4 is about 50% smaller than 4.56. Dana, deal with the weight.

 

[gtxracer]

I suppose the fact that thru the years I have upgraded and kept a close eye on the 8 3/4 in my GTX, leaving at 3200 with a trans brake and not broken anything means, I'm lucky. 1974 was the last time on the street and now it will leave with the wheels up to a best of 10.34 and 60 ft low 1.40's'
But I have acquired a Dana 60 housing from a 3/4 ton Ford pickup and I will be doing a changeover soon, as a safety measure.
Bob