8 3/4 Chrysler pro gears?
 

Does anyone still offer pro gears for the 8 3/4?
Is cryo and rem finishing worth the effort?
Who does cryo and rem finishing on ring and pinions?
Suggestions please

Re: 8 3/4 Chrysler pro gears?
 

Earp Machinery Safford Az. does both. I won't run any oem part before I have it at least cryoed.

Re: 8 3/4 Chrysler pro gears?
 

On the same note what is the prefered brand of 8 3/4 gear if a pro gear is not available or does it matter by the time you have it cryoed and rem polished or micro blued?

Re: 8 3/4 Chrysler pro gears?
 

Strange sells gears that are already REM finished.

Re: 8 3/4 Chrysler pro gears?
 

What Ratio are you looking for? I have a complete rear axle 8 3/4 with a 5.13 with all the things done to it. And I have a few other things. Jeff 985-804-6161 or PM me.

Re: 8 3/4 Chrysler pro gears?
 

I have seen the Pro gears for the 4.86 ratio only on Ebay but they want 6 or 7 hundred bucks for them. I don't think they make them anymore in any ratio for the 8.75 Chrysler rear. Jim

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Re: 8 3/4 Chrysler pro gears?
 

Yea no luck with pro gears, bought standard ones and will have them rem finished and all that jaz.
Anyone use the redline shockproof gear oil? Thin stuff. Wondering if it would be enough. In a stocker.

Re: 8 3/4 Chrysler pro gears?
 

Not a 8 3/4, but I have been running the Redline Heavy Shockproof oil in my low 10 high 9 second bracket car, in a Dana 60 with Pro gears and a 4 speed. Also used it for years in my 85 Mustang stickshift Stocker with a 8.8 rearend and street gears. Very happy with the Redline, but don`t spill it! it will soak into rough concrete and hang around for years, even with pressure washing.

Re: 8 3/4 Chrysler pro gears?
 

http://www.strangeengineering.net/pr...-42-case.html/

went looking for rem finished gear and noticed strange offers a 4:30 pro gear for a 742 case thats not badly priced.

Re: 8 3/4 Chrysler pro gears?
 

Go Dana 60 and forget about the 8.75. The Dana is faster. I have used mine since 1991 and change oil in it every two years, same pro gear all of these years. Going on 26 years of worry free service, cheapest thing I ever bought for the race car

Re: 8 3/4 Chrysler pro gears?
 

On a previous post I stated that Strange offers REM finishes gears. It is really US Gear .

Re: 8 3/4 Chrysler pro gears?
 

Larry how is the Dana faster? Does the fact they roll easier make up for the added weight of the Dana? Not arguing, your car is very fast, just like to get your opinion. We're running the same combo you are in a 71 challenger.

Re: 8 3/4 Chrysler pro gears?
 

I backed to back them at Indy one year between first and second qualifying.

By the time you put good tubes and a back brace on, and relocate the shocks so they don't hit brace the weight difference is not as much as you might think. The last 8 3/4 I broke all was lost: broke every tooth on ring and pinion, spit the thrust side adjuster out after it broke the cap and bent the spool.

Re: 8 3/4 Chrysler pro gears?
 

Gotta agree with Mr. Hill. I think a lot of the reputation of a Dana 60 comes from when a stock Sure Grip limited slip unit is used. (about 40 lbs). On my bracket Fairmont, the first diff was a Ford 9", using a shortened OE Ford housing, a factory Nodular iron case, 33 spline spool and axles. It worked fine with the automatic, but when I switched to the Jerico 4 speed, I figured therearend would be marginal as it was. While pricing out a new braced housing, aftermarket case , bigger axles and spool, a buddy suggested selling the 9" and building a Dana 60. Turned out to be a good move.
My Dana used a 3/4 ton Ford truck housing which has thick axle tubes, 35 spline Strange spool and axles, and a T/A girdle cover. Using the same brakes as the 9" had, the finished Dana weighed a mere 6 pounds more than my 9" did. But keep in mind, if we would have added a brace to my existing 9" housing, installed 35 spline spool & axles, and an iron Strange case, I doubt the 9" would have been any lighter at all. Yes, I am aware that aluminum 9" cases are available, which would shed some weight, but then a car Dana with thinner tubes could have been used as well. I have been using that Dana behind the 4 speed for 17 years now, never dropping the clutch below 6000 RPM, and the only time the cover has been off was for ratio changes, and all 3 gear sets still look like new. I only see 2 downsides to the Dana, selection of ratios not as wide as a 9", most ratio changes will change the trap RPM by 250-300 RPM, a 9" has much more variety and will allow for much closer RPM change. Also setting up a 9" on the bench is easier than doing it under the car, or removing the whole rearend. If you have the money and space, you can have multiple 9" chucks set up ready to go. My Dana cost a fair bit less than my 9" did, in fact, selling my old 9" almost covered the cost of the new Dana.
I know several MoPar racers that spent a lot of money, and broke a lot of pieces with their 8 3/4s, most went the Dana route and have been really happy with the swap. You can always find somebody to buy your good used 8 3/4 stuff, but once its broken, its just scrap metal.

Re: 8 3/4 Chrysler pro gears?
 

Not only the Dana 60 is stronger, but due to the pinion placement, it is more efficient to turn and requires less power when compared to the GM 12 Bolt.

Re: 8 3/4 Chrysler pro gears?
 

...and by the way...there is a drop out Dana 60 assembly available too! :D:D:D

http://www.jratoffroad.com/products/...od&productId=2

Re: 8 3/4 Chrysler pro gears?
 

x2

Re: 8 3/4 Chrysler pro gears?
 

In 1988 I Decided to install a Dana 60 in my 62 dodge. I was running 11.80's @ 3700# was tired of worrying if this was my last pass on a 8 3/4 gear set, my luck it would have broke in the final at a national event. Any way I built a real 66 Dana 60 housing strange axles and spool Richmond 4:88 gears etc. never broke another part in that car. That rear differential in now in my 64 Plymouth AA/SA with a new gear set and bearings just because!
When I installed the Dana in my 62 dodge in 1988 I did it at the track (englishtown) made my first pass with the 8 3/4 , installed the Dana and drive shaft made another pass the car went .012 quicker !! My Dana was about 22# over all heavier then the 8 3/4.
I would never suggest using an 8 3/4 over a Dana 60.

FYI at the allstars race 2 weeks ago my uncle broke his 8 3/4 in his c/sa barracuda and destroyed his transmission case in the process. It is a pro trans with the band modifications etc. the case alone is 1/3 the cost of setting up a Dana 60. His car will be getting a Dana 60 this year as well.

Re: 8 3/4 Chrysler pro gears?
 

hi, not to highjack this. dana came in four case sizes. the 67 to 72 ford 1/2 ton pickup is the lightest, followed by mopar case fpr B and E body cars, then 3/4 ton pickups, followed by 1 ton pickups. I changed from 8 3/4 to dana 60 years ago, I weighed both, both had spools, there was only 32 # more, with dana, the car ran exactly the same ET and MPH . the ford , has 3 " tubes, never twisted them. I used the ford case.

Re: 8 3/4 Chrysler pro gears?
 

What about the s60 version from Strange? Are they legal in stock, as strong and reliable as an old school Dana?

kurt

Re: 8 3/4 Chrysler pro gears?
 

I also have a complete Moser Dana 60 w/5.13 pro gear axle to axle. Call for more info.

Re: 8 3/4 Chrysler pro gears?
 

All this bad vibe has made me change direction, going with Dana instead. Always heard the 8-3/4 was more efficient.

Re: 8 3/4 Chrysler pro gears?
 

I read a dedicated article comparing rear end efficiency in one of the old car magazines a long time ago. Of the rears that I remember they tested, this was the order of efficiency:

1) GM 12 bolt
2) Dana 60
3) Chrysler 8 3/4
4) Ford 9"

I believe it said that the biggest factor is the placement of the pinion in relationship to the ring gear. The higher the pinion (closer to center), the more efficient it is. The 9" has the additional disadvantage of an extra pinion bearing.

I don't recall what others were tested.

Somebody makes/made a 12 bolt style center section for 9" housings. Was it Jim Kinnett that had a 12 bolt or a Chrysler 9 1/4 rear in his SS/AA Cuda?

Re: 8 3/4 Chrysler pro gears?
 

Kinnett ran a 12 bolt GM rear in both the Hemi SS car and the Pro Stocker. I have seen them both personally. Jim

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Re: 8 3/4 Chrysler pro gears?
 

Re: 8 3/4 Chrysler pro gears?
 

It's called hypoid distance. Dana 60 is 1.125". MoPar 8 3/4, GM 12 bolt and 10 bolt, AMC Model 20 are 1.50". Ford 9" is 2.25". The farther the pinion is from the centerline of the ring gear, the greater the angle of the drive teeth to the ring gear teeth and more friction. Bearing size is a factor for efficiency as well as rotating mass.
I remember that same article, but have since learned from other sources who have done serious experimentation that the Dana 60 is more efficient than the 12 bolt.

Re: 8 3/4 Chrysler pro gears?
 

Dwight is correct; after much analysis, the final result is the Dana 60 is the most efficient of the bunch.

Re: 8 3/4 Chrysler pro gears?
 

Bob,

The Strange 12-Bolt, 9" drop out has weight limitations on its use.
It's designed for very lightweight cars, dragsters and roadsters.

Re: 8 3/4 Chrysler pro gears?
 

Maybe someone will make more ratios again. Picked up another Dana housing yesterday, free

Re: 8 3/4 Chrysler pro gears?
 

I remember reading that Rick Johnson ran a 9 1/4 Mopar rear in his SS/AA Barracuda at one time. He may still.

Re: 8 3/4 Chrysler pro gears?
 

DeFrank and Cohen had a 9 1/4 in their AA Cuda. I remember looking at it during a points race at Irwindale in the 70's.

There have been many articles about the low drag of the Dana 60. there was an article in one of the Mopar magazines where they took out the 8 3/4 and back to backed it with a Dana 60. the Dana was almost a tenth quicker even with the added weight. If you use the right parts you can get a Dana within 15 pounds of a prepped 8 3/4.

Re: 8 3/4 Chrysler pro gears?