489 vs. 741

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65Vart

65Vart

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Hey guys , another rear end question.
Can I take my 741 suregrip and put it in a 489 case? I'm worried about the 741 if the car gos to the track. With a slick on the car I have heard bad things about the smaller pinion/yoke with no wheel spin. I just picked up a 489/323 open that I thought I was going to sell..........not sure now.
 
i just found a big yoke to put on, havent broke anything yet... it takes side steps off the clutch at 4500 with slicks.

knock on wood...
 
65Vart said:
Hey guys , another rear end question.
Can I take my 741 suregrip and put it in a 489 case? I'm worried about the 741 if the car gos to the track. With a slick on the car I have heard bad things about the smaller pinion/yoke with no wheel spin. I just picked up a 489/323 open that I thought I was going to sell..........not sure now.
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You can take the SG unit out of the 741 case, but the gears will not work between the 2 cases so you would end up with a 3:23 SG in a 489 case. My opinion on the 741 is that the smaller pinion shaft can handle most anything thrown at it, unless it's a monster motor, it's the smaller U-joint that may give out. Good luck with your project, Geof
 
I,ve never done the 741-489 switcheroo,741 in a 489 case.If you get stuck for a 489 yoke 65Vart?I have a spare.(will it fit .741)?
 
I've been beatin the crap out of my small pinion for years. While it has not seen slicks or super stick conditions, it's been a good 15 years with it and some decent pumped up small block power.

Side steppin the clutch @ 7 G hasn't hurt it yet.
 
You can swap the SG unit from the 741 to the 489 gear/case assembly. Can you set up gears? If not, might be better to sell it, and get the 489 rebuilt with a new SG unit. The early '60s cars, like Max Wedge vehicles only had 741 size pinions. Even the 489 pinion tapers down to the 741 pinion size at the yoke. You can swap to the big yoke on the 741 case, and that's what I'd do.
 
rumblefish360 said:
I've been beatin the crap out of my small pinion for years. While it has not seen slicks or super stick conditions, it's been a good 15 years with it and some decent pumped up small block power.

Side steppin the clutch @ 7 G hasn't hurt it yet.
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Wow Rumble! Come on! You have a 7G motor and haven't put stickies on it yet? You must have to feather the throttle. SLICKS! SLICKS! SLICKS! Put yer kidneys in the seat back! :-D:-D:-D:-D:-D
 
Where is a good place to buy a yoke like that? I just picked up a 741 with 2.94 open gears out of a 66 Belvedere.. needs some tlc, and a new yoke.. also had to hammer the brake drums off it, lol. will definitely need new wheel studs.
 
You can swap in a sure-grip from any 8-3/4 case easily into your 489 case. And to note when swapping in a sure grip for an open there's no reason to have to setup gears again because your not changing the pinion depth. All you have to do is set the backlash which is a simple job with a dial indicator. I've done it a few times and it always worked fine for me. Also the 489 pinion may have the same diameter section at the front but the rear bearing section is much thicker and that's far more important because that's where the major pressure is. The pinion gear under a load is being pressed sideways against the ring gear so the thicker rear section of the 489 pinion will take much more pressure than a 741's thinner section. Nevertheless a 741 is still a very strong unit (much better than alot of guys give it credit) but if your going to run slicks and have a 489 I'd do the swap to be safe and sell the 741.
 
72BlueSwinger said:
Where is a good place to buy a yoke like that? I just picked up a 741 with 2.94 open gears out of a 66 Belvedere.. needs some tlc, and a new yoke.. also had to hammer the brake drums off it, lol. will definitely need new wheel studs.
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Which yoke do you need? The small or large one? 10 or 29 spline? I have a very nice 10 spline small yoke with Moroso girdles installed for sale. If that's what you need PM me your e-mail address and I can send you a picture.

Thanks, Tracy
 
sumbitmopar said:
Hey 65Vart, what kind of HP and Torque does your motor make?
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The car has a little mild 273 solid lifter motor in it right now with a 4 spd. It moves the car around and sounds good 8). I want to build the car for the motor I will eventually have in there. I bought some KH disk brakes complete with DB spindles,rotors etc and I now have a complete Drum to Drum 8 3/4 SG with some 3:91s. After all of that is done I'll tie the frame and save up for a stroker.
That's the Plan.

65 Vart 005.jpg
 
pettybludart said:
When are you doing the install?My hoilidays are coming up,3 weeksoff I,ll get bored after a week.
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Going up to National Moparts this weekend to get my Interior. I'll see if I can get some shock plates off him. Those and Ubolts and I will be ready to go. Will need to get my DShaft cut but thatll be after she's in. Let me know if you know anybody who wants a set of 3:23s 489 case (open diff). 200$. I found out it's 150 to ship it to the states.
 
rumblefish360 said:
I've been beatin the crap out of my small pinion for years. While it has not seen slicks or super stick conditions, it's been a good 15 years with it and some decent pumped up small block power.

Side steppin the clutch @ 7 G hasn't hurt it yet.
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I've got A 741 going in my car ,isn't it still a good up grade from 8 1/4 ,or should I keep the 8 1/4?
 
dubree 61 said:
I've got A 741 going in my car ,isn't it still a good up grade from 8 1/4 ,or should I keep the 8 1/4?
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With no other information to your question.....
Depends on how much power your putting to it.

One can argue any up grade is a worthy up grade but where does it end?
You’ll also have some *** clown or two hear you say you upgraded from an 8-1/4 to the 8-3/4, *** clown 1 says;
“That was stupid because your not making a lot of power!”
while *** clown 2 will say;
“Why did t you do the DANA & be done with it? What a waste of money!”

Sorry the bottom line is do what makes you happy or feel safer.
 
rumblefish360 said:
With no other information to your question.....
Depends on how much power your putting to it.

One can argue any up grade is a worthy up grade but where does it end?
You’ll also have some *** clown or two hear you say you upgraded from an 8-1/4 to the 8-3/4, *** clown 1 says;
“That was stupid because your not making a lot of power!”
while *** clown 2 will say;
“Why did t you do the DANA & be done with it? What a waste of money!”

Sorry the bottom line is do what makes you happy or feel safer.
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I'm running a 360 with a few up grades nuttin crazy I'm a small block cat love the small motors
 
I was pondering a swap as well. Currently have 741 323 SG in the 67 cuda.
I have a 489 323 SG that's sitting on Jack stands. It' from my 69 cuda. I was thinking of getting a 355 setup and being able to swap them between the 489 and 741.
 
4spdragtop said:
I was pondering a swap as well. Currently have 741 323 SG in the 67 cuda.
I have a 489 323 SG that's sitting on Jack stands. It' from my 69 cuda. I was thinking of getting a 355 setup and being able to swap them between the 489 and 741.
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You will be surprized on the low to mid range pull with 3.55 gears :)
just a great street gear period.
 
If your going to hammer on a 489 you need to use the crush sleave eliminator.

I've had the sleave split like it was cut by a laser.
 
mycuda said:
any 8 3/4 case is an up grade from a 8 1/4.
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My 8 3/4 has a 391 the 8 1/4 I think was a 291 it was out of a 6 cyl auto car for me it was geared to high so instead of changing gears I just bought the 8 3/4 I picked up a 9 1/4 from a Cordoba cost was to high for cut down and new axles
 
RustyRatRod said:
Saying the 741 is "weak" is simply spreading mis-information. Straight from Dr Diff:

Pinion Comparison - Quality Body Shop Drivetrain
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No ****!!!

Another episode in the mopar lore of misinformation, akin to 340 intakes on 318 heads is horrible... :)

The day the pinion bearing size becomes the weak point in a 741 case is the day the earth stops rotating. It's not the weak point in ANY of the cases!
 
Well, it is, but not note worthy nevermind worrisome!!! I have had my 741 equipped with 4.10’s and beating the snot out of it for about 25 years now.
 
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