temporary hold up

[69clone]

Hello every body,
I would like to get my new engine in this month and I am trying to decide if I should do this or is it a dumb idea. I have a 498ci (626hp/640tq) reverse manual 727. Now the problem I have is I am afraid of breaking this 8 3/4 rear I have and want to get a dana in there before I race it with sticky tires. Now I don't want to spend 400 bucks on a new driveshaft to later put a dana in there and need a new one, so could I get away with one of these original 69' roadrunner driveshafts on ebay for 100 bucks (how strong is an original? they held up to hemis). The next issue is the 8 3/4, it looks to be in pretty good shape (needs new seals and such) but what is the weak link in them? Basically what will I end up breaking? Or do I need to postpone this and do it right from the beginning?

 

[Budnicks]

the 8-3/4" 742 {especially the Aluminum unit} or 489 carriers done correctly will be fine, unless you are running big 33'x16" slicks all the time, making 750 #'s of torque or something like that, I still wouldn't really worry too much... you can back brace the housing, put bigger &/or more splined harder axles & use a Spicer 2790 or 1350 style universals, larger 3"x0.065 chrome-moly or quality 3"x0.125" Aluminum driveshaft, for reciprocating weight reduction & strength too... I've put 1000+hp thru an 8-3/4" & didn't break or bend it, the Dana-60 is a great rear end, heavy too thou, try Strange S-60, great deal for the money, if you go that route.... you could go with a Moser-MO875 & the MRE Alum. MP 742 carrier, save some weight money & still have a trick & strong rear end...

 

[69clone]

Thanks Budnicks! I was even thinking about converting a newer dana out of a truck to work which apparently would cost about as much as a suregrip for the 8 3/4. I wouldn't be running anything that radical, just whatever I can fit under the stock wheel wells (10" wide I believe?) with mid 3:55-73 gears. I was just reading that some people claim the gears and axles tend to be the issue areas when it comes to breaking? Would a back brace and quality gears help reduce that or is that just a problem you run into with 8 3/4? I do have a 489 center that I would use for racing and a open 741? I planned on running on the street.

 

[dvw]

Hello every body,
I would like to get my new engine in this month and I am trying to decide if I should do this or is it a dumb idea. I have a 498ci (626hp/640tq) reverse manual 727. Now the problem I have is I am afraid of breaking this 8 3/4 rear I have and want to get a dana in there before I race it with sticky tires. Now I don't want to spend 400 bucks on a new driveshaft to later put a dana in there and need a new one, so could I get away with one of these original 69' roadrunner driveshafts on ebay for 100 bucks (how strong is an original? they held up to hemis). The next issue is the 8 3/4, it looks to be in pretty good shape (needs new seals and such) but what is the weak link in them? Basically what will I end up breaking? Or do I need to postpone this and do it right from the beginning?

Two schools of thought. First is spend money to upgrade to a Dana. Take your time, If your handy and look for a junk yard piece and convert it (what I did cost less than $1000, new axles, spool, gear, bearings, studs, gaskets. but free labor) or what my son did swap meet S-60 that had never been in the car, $1200. That being said I've run 8 3/4" with stock driveshafts in 10.80-11.10 cars for years. I've never broke the rear ends, they're still going. The one in the 10.80 car is 15 years old, the 11.10 car (3890lbs) is 10 years old. We have ripped out U-joints due to stock pinion angle, needs 5-7 degrees with leaf springs. Quicker than that I'd start looking for the Dana. I have bent houseings andbroke pinions in low10 cars. If the car is light it might survive, but not 3800-3900.
Doug

 

[Budnicks]

Thanks Budnicks! I was even thinking about converting a newer dana out of a truck to work which apparently would cost about as much as a suregrip for the 8 3/4. I wouldn't be running anything that radical, just whatever I can fit under the stock wheel wells (10" wide I believe?) with mid 3:55-73 gears. I was just reading that some people claim the gears and axles tend to be the issue areas when it comes to breaking? Would a back brace and quality gears help reduce that or is that just a problem you run into with 8 3/4? I do have a 489 center that I would use for racing and a open 741? I planned on running on the street.

yeah the stock axles & stock tubes are the weak links... easy cheap fixes thou

 

[68sportsatelliteragtop]

If you are on a budget, get your car together and drive it while collecting cash/parts for a conversion to a Dana 60. You should be able to find a stock length driveshaft for your car,with the 8 3/4, just don't put the slicks or drag radials on it until you get the rear squared away. The season is short, drive it now and put the rear in next winter, you'll probably want Cal Tracs, or at least SS springs by then anyway.

 

[daredevil]

I think aftermarket caps would be the first thing id change in an 8.75 if i was going that route. Caps are the weak link as they can cause pinion deflection and break gears. Alloy axles are a must too.

 

[69clone]

yeah the stock axles & stock tubes are the weak links... easy cheap fixes thou

Alright cool I will look into it, any companies you prefer? I believe I was looking at axles from Moser.

If you are on a budget, get your car together and drive it while collecting cash/parts for a conversion to a Dana 60. You should be able to find a stock length driveshaft for your car,with the 8 3/4, just don't put the slicks or drag radials on it until you get the rear squared away. The season is short, drive it now and put the rear in next winter, you'll probably want Cal Tracs, or at least SS springs by then anyway.

Exactly my thought, I just hate having it sit on the stand and wanna hear it run.

I think aftermarket caps would be the first thing id change in an 8.75 if i was going that route. Caps are the weak link as they can cause pinion deflection and break gears. Alloy axles are a must too.

Thanks, I did hear the caps were also a weak link. Forgot about that...

Now if I am able to find a dana and install it over winter would it make sense to just use an original driveshaft instead of spending the money on an aftermarket for the 8 3/4? I know it needs to be about an inch or so shorter for the dana?

 

[69clone]

Just came across someone selling a 64' plymouth savory Dana 60 sure grip, drums, etc. complete for 1500 is it worth it? That starts getting close to a brand new unit.

 

[Budnicks]

try Moser Engineering, Strange Engineering & Mark Williams, Dr. Diff current E-Scam listings possibly too {Currie or Lenco ? maybe, not sure anymore, mostly 9" Ford stuff now} you could also try Mancini Racing they always have quality stuff too...

 

[69clone]

Yeah if I remember right they started around 1800 and come with a warranty compared to what probably needs rebuilt and such for nearly the same price.

 

[Budnicks]

IMHFO I'd do a new Strange S-60 "bolt in", before I spent $1500 on a old Dana 60 that you don't know or needs to be rebuilt, unless you know the rear end & the person selling it or it's been gone thru already maybe... you can use your brakes off the 8-3/4 {11' drums, e-brake, backing plate, springs, hardware etc.} on that S-60 probably & save a few bucks too, check 1st thou...

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Just came across someone selling a 64' plymouth savory Dana 60 sure grip, drums, etc. complete for 1500 is it worth it? That starts getting close to a brand new unit.

:iamwithstupid: if you had a 64 & needed a date coded 64 Dana 60 Rear

 

[69clone]

IMHFO I'd do a new Strange S-60 "bolt in", before I spent $1500 on a old Dana 60 that you don't know or needs to be rebuilt, unless you know the rear end & the person selling it or it's been gone thru already maybe... you can use your brakes off the 8-3/4 {11' drums, e-brake, backing plate, springs, hardware etc.} on that S-60 probably & save a few bucks too, check 1st thou...

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:iamwithstupid: if you had a 64 & needed a date coded 64 Dana 60 Rear

Thanks budnick, you're the best! I got in touch with Dr. Diff and the other sites all seem to cost around the same. 1800 or so. I think I'll just have to save up and buy one of those over winter or something. Probably just going to throw the 8 3/4 on for now, run the open 2.76's in it and focus on the carb, converter and such. And just take it easy on the pedal (Probably good for me as I've never driven something this powerful).

 

[Budnicks]

your very welcome... Hell I'm really good at spending other peoples money...LOL...