Posi Unit Fitment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

steveb64 · 03-22-2013, 11:10 AM

I have a line on this:
1984 chevy full size truck rear axle
3:73 posi, 6 bolt pattern
$375 obo

I own a 64 C10 and would like to convert it over to a posi rearend. Will the posi unit in this rearend swap into mine? I currently have the open unit with the factory 3:73 ratio 12 bolt.

Budman56 · 03-22-2013, 11:42 AM

You will need to measure the new transplant to make sure its the same or close to the same measurement as your orginal rear end, I think that the measurement on mine was 65.5" wide but cant remember for shure. Other than the measure ment it should fit fine, you will have to weld new bracket onto the new rear end. I believe that CPP has them or you can cut them off your old rear end and reweld them to the new one that is what I did. anyway I sure that others in here will comment. Good luck with the swap.

bonehead · 03-22-2013, 11:56 AM

I did this swap years ago on my 1961 c-10. I used a 3.73 posi out of a 1983 suburban. I just carefully cut the old perches off the old rear, along with the panhard bar axle mount. I mounted the rear and everything in place, centered up the rear, set the pinion angle to what it was on the old rear, tacked everything in place and then took the rear back out and welded it all solid. Driveshaft bolted right in, adapted the brake lines, and used the emergency brake cables from the old rear end. I believe the new rear will be .75" wider per side, but I used stock wheels so that was not an issue.
Took me about 2 days. Worked for me, good luck.

steveb64 · 03-22-2013, 12:40 PM

Will the posi unit itself fit in my 64 axle housing?

bonehead · 03-22-2013, 12:52 PM

You mean you want to swap the guts of the posi into the 64 rear? I doubt it will fit but I'll leave that to the other experts on this board.

steveb64 · 03-22-2013, 01:01 PM

Quote:

Originally Posted by bonehead

You mean you want to swap the guts of the posi into the 64 rear? I doubt it will fit but I'll leave that to the other experts on this board.

Yes, that is what I am wondering. Thanks for clarifying.

Budman56 · 03-22-2013, 03:21 PM

Quote:

Originally Posted by steveb64

Yes, that is what I am wondering. Thanks for clarifying.

Im no expert, that would be (captain fab), your existing rear end should be a 12 bold eaton so the newer will not fit into the older.

03-22-2013, 11:10 AM	#1
steveb64 Registered User Join Date: Oct 2009 Location: Moline, IL Posts: 157	Posi Unit Fitment I have a line on this: 1984 chevy full size truck rear axle 3:73 posi, 6 bolt pattern $375 obo I own a 64 C10 and would like to convert it over to a posi rearend. Will the posi unit in this rearend swap into mine? I currently have the open unit with the factory 3:73 ratio 12 bolt.

03-22-2013, 11:42 AM	#2
Budman56 Registered User Join Date: Aug 2011 Location: Patterson California Posts: 1,133	Re: Posi Unit Fitment You will need to measure the new transplant to make sure its the same or close to the same measurement as your orginal rear end, I think that the measurement on mine was 65.5" wide but cant remember for shure. Other than the measure ment it should fit fine, you will have to weld new bracket onto the new rear end. I believe that CPP has them or you can cut them off your old rear end and reweld them to the new one that is what I did. anyway I sure that others in here will comment. Good luck with the swap. __________________ MY 65 C20 BUILD http://67-72chevytrucks.com/vboard/s...d.php?t=483346 ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/

03-22-2013, 11:56 AM	#3
bonehead Registered User Join Date: Jun 2007 Location: Charlotte, NC Posts: 516	Re: Posi Unit Fitment I did this swap years ago on my 1961 c-10. I used a 3.73 posi out of a 1983 suburban. I just carefully cut the old perches off the old rear, along with the panhard bar axle mount. I mounted the rear and everything in place, centered up the rear, set the pinion angle to what it was on the old rear, tacked everything in place and then took the rear back out and welded it all solid. Driveshaft bolted right in, adapted the brake lines, and used the emergency brake cables from the old rear end. I believe the new rear will be .75" wider per side, but I used stock wheels so that was not an issue. Took me about 2 days. Worked for me, good luck. __________________ past trucks: 1980 C-10 Silverado SWB 1961 C-10 custom cab LWB 1966 C-10 custom cab LWB Last edited by bonehead; 03-22-2013 at 12:02 PM.

03-22-2013, 12:40 PM	#4
steveb64 Registered User Join Date: Oct 2009 Location: Moline, IL Posts: 157	Re: Posi Unit Fitment Will the posi unit itself fit in my 64 axle housing?

03-22-2013, 12:52 PM	#5
bonehead Registered User Join Date: Jun 2007 Location: Charlotte, NC Posts: 516	Re: Posi Unit Fitment You mean you want to swap the guts of the posi into the 64 rear? I doubt it will fit but I'll leave that to the other experts on this board. __________________ past trucks: 1980 C-10 Silverado SWB 1961 C-10 custom cab LWB 1966 C-10 custom cab LWB



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