Please try and use the search function.
Its all on here if you study the info enough, you just need to sort through the banter to find what you need.
I've got a few minutes thoough, so heres what i think:
You need to decide what ratio you want and if you want a limited slip centre or an open centre.
At the very minimum you need to make/buy a custom moustache bar,
then get a pair of unijoint axles and output shaft-side flanges from a 260z/280zx,
and an r200 'longnose' differential of course.
If you use the old datsun Z type R200 you wont need to modify anything to fit to an existing R160/R180 tailshaft in the 1600.
Bad news with the Z-car R200's are the ratio's are a bit average mainly having 3.5/3.7 etc and all had 'open' centres.
You will need to look for the later 280zx with manual trans to get a 3.9:1 ratio.
If you want other ratio's like 3.9/4.1/4.4 etc you need to look out for import Skylines like the DR30/HR31/Passage/S12 silvia turbo's or late model Z31na (except 88 model).
All of the skyline diffs had different tailshaft flanges so you will need to either cut off the skyline tailshaft unijoint and diff yoke mating flange and weld this onto your existing 1600 tailshaft or alternatively swap the flange/yoke over from the Z-car R200 for it to bolt together.
Those Skyline diffs mentioned are all clutch pack lsd's and are commonly used in competition vehicles due to be easily rebuilt by replacing the clutch/friction discs in side them
and all come with cv axles too which is a great strength upgrade from uni's.
These Skyline cv's differ in design between non turbo and turbo models.
Turbo models being beefier units with thicker axles and larger cv's, companion flanges and stub axle spline diameter.
but you must be prepared to make custom cv axles and mate these to companion flanges like the 6bolt Mr30 Skyline etc. Be aware that Dr30's also have a '6bolt' companion flange but are approx 10mm larger in diameter (which may require grinding clearance on the swing arm) and fit the larger axle shaft spline diameter of 28mm (1600/MR30 is 26mm).
Viscous LSD centres are different and use different output shafts (one noticably longer than the other).
I'd stay clear of these but they can be used so long as you use the matching 'viscous' outputs shafts with the 'viscous' diff centre.
Viscous r200's are commonly found in 88 Z31t and Y31 Cima. The output shaft spline is different too apparently. The details of this are on this site somewhere too.
Also be aware that some R200's like R31na/Y31 etc have different rear covers with two vertical bolt hole mounting points etc.
The maddat moustache bars ive seen to suit 1600 are made to suit the two 'horizontal' stud mount type like Z-car or DR30 etc.
If you get the wrong type you will need to source one of these rear covers also or modify the moustache bar to suit.
There are some high capacity versions with cooling fins on some models like y31 Cima and Z31 lsd's.
If i were you i'd look for a Z-car diff and unijoint axle setup initially which will get you going,
then track down an import skyline diff later with an lsd centre and better ratio's and swap it in down the track and consider cv axles if your still keen or making a fair bit of power or will be using slicks when drag racing etc.
Hope this gives you a rough reference.
regards Nick.
Heres a few threads that might help also:
http://ozdat.com/forum/viewtopic.php?f= ... =r200+260z
http://ozdat.com/forum/viewtopic.php?f= ... =r200+260z
http://www.ozdat.com/forum/viewtopic.php?f=2&t=1261