Yes, H165 centers are intechangeable. The CRP (R&P) gearset alone from Type 1is not interchangeable with Type 2 center.

Yes, there are different width housings. Like Datsun 1500 Roadster is narrower than Vanette housing.

Yes, there are 4.875 centers, but they were mostly from Datsun Competition. And the Vanette from factory.
* 38100-N5505 4.875 R&P SET TYPE I
* 38100-W9300 4.875 R&P SET TYPE II

Tomei sell LSDs.

I have just purchased a h165 rear out of a vanette and was wondering if someone were able to clear a couple of things up.
I believe there is a type 1 and type 2 h165, if this is correct is there a difference in centers, are they interchangeable?
I am planning to put this diff into a sunny sedan, I have measured from wheel to wheel on the sunny and the h165, the h165 is about 90mm wider, is this correct or are there different size h165 housings?
The center in my h165 is a 4.1, are the 4.875 centers obtainable?
Could anyone please steer me to someone who is able to supply a LSD (new or used in good cond) to fit the h165.
Thanks for the help. Sam.