Maybe this will work. Just copied it out of my build thread.
So here's the low down on what i did to get to this point.
First was to find a bearing with a smaller cup/outer race diameter then the srt4 cup, but still used a 1.625 diameter on the bearing/ inner race. Luckily I found one that works and can be bought at autozone.
Next I bored both bearing retainers for the new cup/outer race. Both had to be bored to the existing bore depth, and a .100 shim was made and used between the driver side cup and retainer.
I used the a568 ring gear, and machined the center out, and finish bored it to 4.475". The 4.475" bore has to be on the absolute center of the gear, since this bore will center the gear on the diff. I also machined .050" step at 6.45 diameter into the face of the gear.
This is a pic of the locating hub machined into the srt4 diff. This also needs the be on the absolute center of the diff, since the ring gear locates on this hub.
This pic show the machining needed to the opposite side of the ring gear flange. First there was .100" machined off the thickness of the ring gear flange. The ring gear bolt circle on the Srt4 is 137.5mm and uses a 10mm bolts. The a568 ring gear uses a 139.5mm and a 12mm bolt. So since the a568 use a 2mm bigger bolt and a 2mm bigger bolt circle you can re drill the srt4 diff to the 139.5mm bolt circle (a568), and since it use a bigger bolt hole all the old hole are cut away. Now you need to counterbore the hole .250 deep for use with a set of arp bolts.
Last a little clearancing is needed on the case to clear the ring gear flange.
Couple more pics