Rare parts to be looking for these days. You are the 2nd in a week looking for a R-180 3.90 diff and LSD if your
throwing it in ,as I recall the poster said ..... Since the 3.90 was never a USA street car application ,the Datsun Competition Dept
used to be the only source 40 years ago. Now there are people using the Suby 4 wheel drive front diffs(same as Nissan uses)
and they have a 3.90 .Problem is you have to source a new set of stub flanges I'm told . I have not dealt with anything other than the Nissan street car and Datsun comp diffs ,so I can't comment. I believe two different people have made the modified parts.
The Datsun 4x4 trucks have 4.38 if you want to get some real gear in your car !
Yes, I know! I'd settle for an R200 3.9 LSD, but I really want to avoid the extra weight. I've looked into the Scooby stuff and a mid-2000s WRX had an R180, but even those are hard to come by. I have a source for flanges, though. Don't want a 4.38, though; not doing a drag car.