8 3/4 '489 Sure-grip change/ratio change?

[Shark1010]

Hello!

I've been trying to read on and understand the 8 3/4 centers a bit more as that is where I have always lacked in knowledge.. a little bit of contradicting material out there I have read..

I currently have a '489 center section with a 3:23 cone style sure-grip setup.. bit worn (a lot)...

My question I have been trying to answer is, what is the best set-up up to with on a street car, (400/425ish) engine numbers, for filling a completely empty 489 case?

Any advice would be greatly appreciated on what I would need to completely replace the innards on the 489 case and where from !

Thanks!

 

[mentor70]

get a Eaton Tru Track, with some 3.70 gears. im running this combo in all my projects, then adding overdrive trannys in everything, a Passion overdrive 4 speed in my 65 Net, and a AOD from a 88 mustang GT in my 77 Ford F-100

 

[Shark1010]

get a Eaton Tru Track, with some 3.70 gears. im running this combo in all my projects, then adding overdrive trannys in everything, a Passion overdrive 4 speed in my 65 Net, and a AOD from a 88 mustang GT in my 77 Ford F-100

Such as this one from Dr.Diff i'm assuming.. And if I've read right, there is no issue switching to different gears to get a different ratio and completely replacing everything? I'm also planning on getting a crush sleeve eliminator and this will all be going into my '68 Charger.

Thanks!

 

[1969CoronetR/T]

I switched my 741 case to a Mosier 489 case with 3.55 gears and an Eaton Truetrac. Works great.

 

[Shark1010]

I switched my 741 case to a Mosier 489 case with 3.55 gears and an Eaton Truetrac. Works great.

That's what I'm thinking about exactly! Just wondered if other people liked them as opposed to other set-ups more.

 

[watermelon]

im goin to switch from a 741 to a moser 489 with the truetrac and 3.23 gears too, 1350 series yoke

also gonna buy moser stock axles with green bearings


only thing i dont know is what ujoint is on the end of my driveshaft. it is a 66 coronet with 8.75 rear end and an open diff with 2.76 gears




would i have a 7290 ujoint on the end of my drive shaft or 7260 series?




let me know what you have when you get yours pulled apart. just curious.


thanks,

watermelon

 

[1969CoronetR/T]

I would get a new driveshaft. Mine was only a few hundred dollars.

 

[coloradodave]

I just installed an Eaton TrueTrac as well. Works as advertised. No noise, no clunking on cornering and no Mopar additive. Mines a 489 case in a Moser fabbed rearend. Info here: http://www.eaton.eu/Eaton/ProductsServices/Vehicle/Differentials/detroit-truetrac/index.htm

 

[CoronetDarter]

Hello!

I've been trying to read on and understand the 8 3/4 centers a bit more as that is where I have always lacked in knowledge.. a little bit of contradicting material out there I have read..

I currently have a '489 center section with a 3:23 cone style sure-grip setup.. bit worn (a lot)...

My question I have been trying to answer is, what is the best set-up up to with on a street car, (400/425ish) engine numbers, for filling a completely empty 489 case?

Any advice would be greatly appreciated on what I would need to completely replace the innards on the 489 case and where from !

Thanks!

Over the course of the last two weekends I swapped the 489 pigs between my Dart and Coronet. The original Chrysler Power-Lok SG can be rebuilt, cheaper than a new aftermarket SG unit.
If not done already, convert the axle bearings over to the 'green' sealed bearings; eliminates the end-play adjustment needed on the OEM tapered bearings.
As for gear ratio, the right gear selection depends upon the size of your cam, stall if it's an automatic, whether or not you're running an overdrive, amount of freeway driving you're planning on. You could set up two pigs, one with 3.23's another with 3.91/4.11 and swap 'em when needed. It was my first time swapping pigs and it was pretty straightforward.
My Coronet has a fairly mild stick - 228/232 @ 0.50"; .530 lift and a 2,800 stall converter. With the 3.23's it was doggin' off the line; didn't wake up until 30+ mph. With the 3.55's it's like a different car. Love 'em! The other benefit is that I'm running a TB EFI and the ECU was always 'hunting' for the right RPM range; with the gears matched to the cam the EFI system is having an easier time learning.[/QUOTE]

 

[watermelon]

anyone using a 7260/1350 ujoint combo or 7290/1350 ujoint combo?


my apologies for hijacking the thread.