I'm almost positive the front suspension from a B210 will not just bolt in. I don't have a b210 so I can't be certain.
If you have both the b210 and 1200 sitting in the same driveway, it should be easy to confirm.
It's all about, find your tape measure and get to work

Righto olboy I"ll explain, currently I'm supervising a $13m refit at work, part of this is buying a couple of million dollars of machinary from America, so I got in contact with the American supplier and asked if I got a gearbox to him can he throw it in the next container coming over. OK not a problem he says, so I had a exciting bid on ebay and won, i would not have even bid if i didn't have the "free" trip home for it, it would cost to much to get it sent over. If i knew of more i would get them sent over as well, but i don't! So thats how i come to get a 63 box for $395.00 Aussie. It is only a spare for the rallycar but it's a good spare to have lying around.

Leosnake, congrats on getting the whole car, man thats fantastic, why it is good is because you can the use the 63series flywheel and pressure plate, with out re-drilling a standard flywheel, because the input shaft is bigger on the 63 stuff (same as L series) you can use a standard A-series flywheel but not the pressure plate because the input spline is bigger. On my original flywheel I fitted a 180b pressure plate to the standard (but VERY lightened) flywheel. As for the fork i'm sure if you hunt around the wrecking yards at the L- series stuff you"ll find what your looking for. Took me a while to find the right doner but i got their in the end.

It is more than 20 years ago since I fiited my 63A box up to an A14 engine, but I definitely used a lightened A12 flywheel (the std A14 one is like a ship's anchor in comparison).
Like you Lemonhead I used a L18 series clutch plate and cover.

kb110, you are right, you can use a standard flywheel and fit a L18 pressure plate, I didn't explain myself well enough (have edited posting)

To go waay back in this thread, My release fork snapped off one of the arms at one time and I just wandered around a wrecking yard that specializes in Nissans until I found one that was closest in terms of fulcrum length to my busted one. I have no idea model Nissan it was out of - lay in a box of many