8.75 439 question.

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dowboy1970

dowboy1970

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Can someone please tell me if I can run a none taper 1.75 pinion gear in a 439 chunk?
I understand the bearings will have to be correct. I have read on the net that some of the early 439s came with the 1.75 pinion gear while they where being fazed out to the larger taper shaft with crush sleeve.
Please help, I am ready to put my rear together, just need to know if I need new gears or just a different set of pinion bearings.

Thanks in advance.
 
dowboy1970 said:
Can someone please tell me if I can run a none taper 1.75 pinion gear in a 439 chunk?
I understand the bearings will have to be correct. I have read on the net that some of the early 439s came with the 1.75 pinion gear while they where being fazed out to the larger taper shaft with crush sleeve.
Please help, I am ready to put my rear together, just need to know if I need new gears or just a different set of pinion bearings.

Thanks in advance.
Click to expand...
I mean 489 chunk, Sorry my bad. Come guys. Someone please help
 
SGBARRACUDA said:
Why don't you just get a 742 case and build that?
Click to expand...
Looks like that is what I am going to have to do. I have one laying in the shop. I will clean it up and compare the two in the pinion bearing areas. My father inlaw had a set of 3.91 gears he thought were for a 489 and I started cleaning up my 489 before the gears got to me in the mail. I have already bought a install kit for the 489 as well. Looks like I am going to have to get a 742 install kit and a set of 489 gears and build both of the chunks.
I guess we live and learn.
 
the pinion for the 489 has rear bearing with a 1.875" i.d., 742 pinion rear bearing i.d. is 1.75", do not know o.d. front bearings are also different. if there are adapter bearings we have never heard of them, and then there is the question of distances between bearings
 
I don't believe you can do that. If I'm not mistaken the pinions rear bearing race OD is different on 742 vs 489 so they won't swap from case to case. With you were close cause I have a nice cleaned up and painted 742 case I'd swap you for your 489
 
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