741 Case Worth Making Sure Grip?

[monaco66coupe]

741 was standard even on the 383 four speeds, and they can take abuse. I found that all the C body cars I've had used 742 cases, at least the 383 and 440 cars, so you could put something together that way if you want the 1 3/4 vs 1 3/8. My 383 GTS has a 741 case, but I didn't realize the housings twisted under hard use, but I'm old and 40mph is about it for me.lol

 

[charger360]

i sell all my 742 and 489 centers because folks seem to go nutty about them i run the 741's in my cars never had a problem even with some stout engines in some heavy cars! if iwas going really high hp with slicks i would go Dana.

 

[myfeather626]

I found this interesting as I have never seen anyone break a 741? I guess a 742 is really strong but I dump the Clutch at least once a day and burn the Bolognese off!

 

[33 IMP]

Real old thread.....but yeah, the 741 being weak is very undeserved, imo. The problem is gear selection. Choice of only two ratios available new.

 

[Cranky]

the 741 is not exactly weak. I also used to sell all the 42 and 89 stuff and keep the 41s for me and I beat the snot out of them and never had one break. With the high horsepower cars on slicks you stand the chance of shaving teeth off the ring gear especially with a 4-speed car and launching at high RPM and it doesn't matter what 8 3/4 you have behind that four speed....

 

[cosgig]

Didn't the max wedges use the 741?

Max Wedge cars used the 657 rear end, which is exactly the same as the 741. It was the only rear available in 63 and 64, until the 742 came out, and of course the Dana for Hemi cars. 741’s have withstood dozens of neutral drops from push button Max Wedge cars, that was the preferred launch back in the day, rev it up and hit the button. I’d say you’ll be fine!

 

[Cranky]

M741’s have withstood dozens of neutral drops from push button Max Wedge cars, that was the preferred launch back in the day, rev it up and hit the button. I’d say you’ll be fine!

And from what I understand they outlawed that method after a couple or so transmission explosions. I've done my fair share of neutral drops too and also did a few 'hit reverse while going forward and throttle matted then going back into drive' sessions. Created plenty of tire smoke for sure lol

 

[watermelon]

741 + 2.94 + true trac center here

440 to TKO500 … burnout


good thread bump


watermelon

 

[RemCharger]

It's the deflection of the case as noted. Spitting teeth. Sometimes blowing the caps out the back.
But shearing the pinion shaft off? Not so common.

 

[Cranky]

It's the deflection of the case as noted. Spitting teeth. Sometimes blowing the caps out the back.
But shearing the pinion shaft off? Not so common.

Are you familiar with the 8" Ford rears? They are just a smaller version of the 9". One time a buddy spit out the drive shaft running a 289 3 speed in a 67 Fairlane while going to work. When he pulled over and started walking back to get the shaft, he noticed something odd looking. It pulled the whole pinion gear out of the case with the pinion support still attached. Yup, ripped it right out of the 3rd member case. Who saw the episode on Road Kill where the stock limited slip unit was sheared? That was on a 9". Never seen anything like that with a 8 3/4 or a D60....

 

[33 IMP]

I have seen the pinion pulled out of a 9" case at my friends rear3nd shop, and on TV (I think it was on Pinks). That's why there are upgraded Daytona pinion retainers, maybe even more important than the nodular case (all 8 3/4s are nodular iron).
Also, Ford "posi's" aren't particularly strong. I have a locker in one of mine, a spool in the other.

 

[Cranky]

I have seen the pinion pulled out of a 9" case at my friends rear3nd shop, and on TV (I think it was on Pinks). That's why there are upgraded Daytona pinion retainers, maybe even more important than the nodular case (all 8 3/4s are nodular iron).
Also, Ford "posi's" aren't particularly strong. I have a locker in one of mine, a spool in the other.

The first time I saw a Ford factory limit slip unit my thought was how does that even stay together.

 

[RemCharger]

Are you familiar with the 8" Ford rears? They are just a smaller version of the 9". One time a buddy spit out the drive shaft running a 289 3 speed in a 67 Fairlane while going to work. When he pulled over and started walking back to get the shaft, he noticed something odd looking. It pulled the whole pinion gear out of the case with the pinion support still attached. Yup, ripped it right out of the 3rd member case. Who saw the episode on Road Kill where the stock limited slip unit was sheared? That was on a 9". Never seen anything like that with a 8 3/4 or a D60....

yup seen enough of that nonsense. I remember going to an outlaw track where a lot of the participants came out of the garages with homebuilt rarely used stuff.. and by the end of the day there was a small pile of swept up crap, mostly 9" pinion and supports. Oddly enough no chrysler parts.
I was running a heavy dose of the good stuff on my 906 head 383 all steel charger, bouncing my way to 10.80s( imagine all 4 wheels off the ground) came home to find the stock small joint driveshaft, stock 8 3/4, all ok.
Down the road I found a slight twist on the DS axle.

 

[threewood]

Nothing wrong with a 741 on the street or even on the track. I have a 741 in my 69 GTX, TruTrac differential, 3.55 gears behind a healthy street motor. No problems even on street legal M/T slicks. I did replace the yolk with a billet one from Mancini since the stocker looked rough.

 

[YY1]

Didn't see it mentioned but...

3.73 was never a factory option so finding one of those used is somewhat unlikely since it would be fairly new using fairly recent aftermarket R&P.

 

[QuickBpBp]

A 741 with a crush sleeve goes along the line of having a factory 440 Hemi back in the day….

 

[Cranky]

I think you will be fine just putting a auburn cone type limited slip it will give you 2 black marks on the road quiet operation unless your putting slicks on I doubt you will break it. I have the same setup in my Challenger with 383 and a hard shifting trans no leaks no complaints no noise. Since your not changing pinion putting one in yourself is actually fairly easy with minimal tool purchase and a FSM. Mopar action did a arrival on this a while back wouldn't hurt to scare up a copy.

Years ago I built and maintained the rear end of a buddies 70 Challenger with a 440 6 pack/automatic that he raced. It was also fully loaded. It ran mid 11's with an 8 3/4 and cone SG. It went for several years until the 8 3/4 started to one leg it and he stopped running it until I could repair it. He stopped running it until he felt it not locking up. It surprised me how good it looked inside except for the cones facing up. Machined the cones .030" and put it back together and it went for many more years. The car was also driven on the street until he couldn't stand how much worth it became and sold it.