Just going to cover what I learned trying to do an IRS swap.
There were a few different IRS housing My choice is probably not the best but all of the info should translate.
I had a Lincoln Mark VIII at some point I bought a spare pumpkin and a 28 spline LSD off ebay. I would recommend finding an Explorer with the 31 spline. You can swap between the 28 spline and the 31 the axles are the same size at the seals. Just change out the center section.
The stock ford out drive is a tripod joint. These were difficult to find stuff that would work with them. I was looking at custom axles and struggling to find parts.
Enter the 930 CV joint.
If you can get your outer axles to a 930 cv joint and buy the 930cv joint out drive stub axles from the drive shaft shop you can buy axles in pretty much 1/2" increments.
www.driveshaftshop.com
What is a 930 CV and how do I find them. They were originally used 930 Porsches but they are used in lots of OEM axles. The big V8 5 series (540 e34) BMWs and the 7 series (e32) had 930 joints They will have at 6 x 94mm bolt pattern and a ~108mm OD
You could buy them new from lots of the off-road places but things get pricey quick when you have to buy 4 of them plus boots ect. I recommend grabbing some axles from the junk yard for all of the hardware.
Then you can take them apart clean and regrease them.
When measuring for you axles measure inside both stub axles without the joints on where they are the the least distance apart usually parallel. Then subtract a 1/2 in off this will ensure that your axles cant bottom out under suspension travel.
Visual of the measurement:
Now you can order axles. I got mine from appletreeauto.com https://www.appletreeauto.com/23-AXLES-28-SPLINE-PAIR-16-2217-0/ they are EMPI brand others are out there from kartek swayaway ect and they come in pretty small increments. I think Cip1 has full kits with the CVS and boots if you didnt find any at the junkyard.
Unless you are buying 300M they are all 4130 chromoly so don't over pay.
now you can assemble everything. There is such a thing as clocking on the CVs so make sure to line them up right
now put your boots on then your joints
You will want some metal bands to hold then boots on not hose clamps. I found these tools worked pretty good.
Don't forget some fresh bolts to put it altogether is sucks cutting of a bolt head that stripped out.
For the drive shaft there is are a few options I went with the 1310 joint that is the spicer 2-2-949 flange yoke that fits the smaller car pattern. If you want to go with a 1350 you will need a bigger front flange and a different adapter.
In they end I probably have a little over 1500 in the swap. So not the cheapest option but it is an option for IRS cars to go to the 8.8
There were a few different IRS housing My choice is probably not the best but all of the info should translate.
I had a Lincoln Mark VIII at some point I bought a spare pumpkin and a 28 spline LSD off ebay. I would recommend finding an Explorer with the 31 spline. You can swap between the 28 spline and the 31 the axles are the same size at the seals. Just change out the center section.
The stock ford out drive is a tripod joint. These were difficult to find stuff that would work with them. I was looking at custom axles and struggling to find parts.
Enter the 930 CV joint.
If you can get your outer axles to a 930 cv joint and buy the 930cv joint out drive stub axles from the drive shaft shop you can buy axles in pretty much 1/2" increments.
The Driveshaft Shop | 2003-2004 Cobra 8.8 inner CV mount for 108mm or Porsche 930 CV joint (spline is 300M) - Ford - Domestic Axles
This is the DSS 31 spline CV stub for the 8.8 rear in 31 spline, this is the improved version used in the Pro-kits with 31 spline (can be bought with a special CV to fit a Stock Cobra or any of our Mustang kits)
What is a 930 CV and how do I find them. They were originally used 930 Porsches but they are used in lots of OEM axles. The big V8 5 series (540 e34) BMWs and the 7 series (e32) had 930 joints They will have at 6 x 94mm bolt pattern and a ~108mm OD
You could buy them new from lots of the off-road places but things get pricey quick when you have to buy 4 of them plus boots ect. I recommend grabbing some axles from the junk yard for all of the hardware.
Then you can take them apart clean and regrease them.
When measuring for you axles measure inside both stub axles without the joints on where they are the the least distance apart usually parallel. Then subtract a 1/2 in off this will ensure that your axles cant bottom out under suspension travel.
Visual of the measurement:
Now you can order axles. I got mine from appletreeauto.com https://www.appletreeauto.com/23-AXLES-28-SPLINE-PAIR-16-2217-0/ they are EMPI brand others are out there from kartek swayaway ect and they come in pretty small increments. I think Cip1 has full kits with the CVS and boots if you didnt find any at the junkyard.
Unless you are buying 300M they are all 4130 chromoly so don't over pay.
now you can assemble everything. There is such a thing as clocking on the CVs so make sure to line them up right
now put your boots on then your joints
You will want some metal bands to hold then boots on not hose clamps. I found these tools worked pretty good.
Don't forget some fresh bolts to put it altogether is sucks cutting of a bolt head that stripped out.
For the drive shaft there is are a few options I went with the 1310 joint that is the spicer 2-2-949 flange yoke that fits the smaller car pattern. If you want to go with a 1350 you will need a bigger front flange and a different adapter.
In they end I probably have a little over 1500 in the swap. So not the cheapest option but it is an option for IRS cars to go to the 8.8
