489 case

[70bee]

what is the strongest case for 8.75 im told it is the 489 case is that true

 

[69HEMICORONETR/TCONV]

489s use the largest pinion diameter, so 489 would be your best choice for for a 8 3/4, they are found in 1969s and up.

 

[Meep-Meep]

Yep, the 489 is considered top dawg and has a 1 7/8" tapered pinion, but if you find a 742 with the 1 3/4" straight pinion it will be OK too - unless of course you have that 830 HP "STREET" HEMI and want to leave hard with slicks :grin:

 

[Gary_gtx67]

1 3/4" straight pinion Please Explain what you mean by this. Mr MEEP-MEEP

 

[Gary_gtx67]

also what were all the vehicles that the 489 casting was in? Whats a good price for a used one?

 

[Meep-Meep]

1 3/4" straight pinion Please Explain what you mean by this. Mr MEEP-MEEP

If you look at the part of the pinion shaft between the bearings it will be a consistent diameter, i.e without taper, or straight. The 741 is 1-3/8" straight.

FYI: Both the 741 and 742 use shims to set pinion bearing preload which takes the worry out of disturbing the preload when changing yokes. The 489 uses a crush sleeve and disturbing the large nut holding the yoke is not a good idea.

 

[Gary_gtx67]

wow that is really good to know!! thanks. what about the types of cars that sed the 489 casting and whaat was the last year mopar used the 3.75 rear end?

 

[69HEMICORONETR/TCONV]

wow that is really good to know!! thanks. what about the types of cars that sed the 489 casting and whaat was the last year mopar used the 3.75 rear end?

1969 and up has the 489 case.

 

[69 Runner]

I never heard of a 3.75

 

[69HEMICORONETR/TCONV]

I never heard of a 3.75

Those were in the Economy models, ...Good catch on the Typo :rolling:



I missed it.:edgy:

 

[Gary_gtx67]

Sorry haha!! It was late!!!

 

[Meep-Meep]

I believe 74 was the last year for the 3.75" - I mean 8.75" rear end :rolling: and the last car to get it was the E body if I'm not mistaken.