saw this online...not sure its related:
Datsun 1200
The Datsun A-series Engine
Believe it or not, the Datsun 1200 is actually very closely related to the Austin/Morris A-series engine. The Datsun A10 engine was rated at around 1000cc and apart from superior manufacturing and machining processes, was in fact a clone of the good old 850 and 948cc engines of the late 1950's.
The Japanese, with their know-how of taking a good idea and making it great, transformed the ageing BMC lump into a fairly good performing, high(ish)-revving engine of 1170cc. This powered a range of Datsuns from the early 1200 series of cars through to the 120Y and Sunny family-cars.
When transplanted into the Minor, the slightly lighter body and the lower ratio differential results in a liveliness from the Datsun 1200/120Y engine that hadn't previously been seen in it's mid-size vehicle incarnation.
A Datsun-powered Morrie is a Morrie transformed; capable of cruising happily at 115kph/70mph all day, and even 170kph/105mph with little modification.
Which is Best - 1200 or 120Y?
It doesn't really matter which version of the engine you get, although you should probably go for as late a model as possible, simply because it's far less likely to have done HUGE numbers of miles. That said though, it's still fairly easy and cheap to fit new rings and bearings to all of the Datsun engines, and you'll probably want to do that as a matter of course once everything is set up for your Minor.
Fitting the Engine and Gearbox
There is a subtle difference between the blocks of the 1200 and 120Y, and this is in the area of engine mountings. Depending on which block you have, when using Ford Escort or Cortina engine mounts, the engine will sit either WAY down in the engine bay, or will be lopsided. Both cases will mean when fitting the engine mounts to your Minor you will have to weld the mounts on top of an 'n'-shaped piece of thick steel (preferably at least 3mm thick).
When fitting the engine and gearbox, you may also find (depending on how high the engine is placed in the engine bay) that the top of the gearbox fouls on the Minor steering rack. This is easily fixed by shaving some of the excess aluminium from the ridge that runs down the top of the box'. In extreme cases you may have to actually cut a hole in the top of the 'box. Don't worry, the 'box is not load-bearing and wont collapse (not unless it's a really HUGE hole, in which case there's something wrong with your setup elsewhere!!). If you do end up opening a hole in the box, you may like to think about cutting out a piece of sheet aluminium and riveting or glueing it over the hole to keep dirt and grime away from the clutch mechanism.
When positioning the engine in the engine bay, it will be necessary to push the engine as far back in the engine bay as possible in order for the fan blades to clear the radiator. DO NOT DRILL HOLES OR WELD THE ENGINE MOUNTS IN PLACE YET !!
Mark out where you think the engine mounts should be positioned, but this may have to be shifted slightly when fitting the gearbox cross member and the drive shaft.
Gearbox Cross Member and Drive Shaft
Depending on the type of engine/box you have, you may be able to use the original Minor gearbox Cross member. The later model Datsun 120Y engines had the Cross member mounting positions located further back on the gearbox than the earlier 1200-series engines. These later gearbox mountings are in almost exactly the right spot for bolting to the existing Minor Cross member. Just a couple of extra long bolts and a rubber bush is required to secure the gearbox in place. At this stage I recommend you offer up the Datsun drive shaft to the Minor diff'. It should bolt up directly to the Minor diff', although you may require slightly longer bolts.
Fit the nose of the drive shaft into the back of the gearbox and adjust the position of the engine & 'box so that there is 15 - 20mm of slide movement on the drive shaft splines. This will then give you the required position of the engine mounts. Of course this may have positioned the engine too far forward and the fan blades will foul the radiator. In this case you will either have to fit an electric fan (I suggest in front of the radiator, behind the grill slats), or find yourself a thinner core radiator from a late model vehicle (the standard Minor radiator does an excellent job of cooling the water, and a thinner one shouldn't provide any significant cooling problems. If you're worried, you may like to fit an extra-wide radiator).
Clutch Linkage
You can leave the clutch linkage as-is on the Datsun 'box, but this will result in the lever exiting the 'box high up on the driver's side against the floor pan. If you cut a slot diagonally opposite the current lever slot in the bell housing and rotate the clutch release fork and lever 180 degrees the lever will exit the bell housing at the lower left (passenger side). You will have to build up a pivot point in the bell housing for the clutch fork/lever and also drill and tap two holes in the outside of the bell housing to accept the clutch cable bracket. There is a convenient flat casting in exactly the right spot for this. You will also have to make up a bracket to hold the clutch cable in place. This only needs to be a simple 'L' shape, but you should make it out of 2mm thick steel, at least.
Well, that's the basics of it. I know there's a few murky bits in the text, but because of the infinite number of combinations of engine, gearbox, drive shaft, engine mounts and Minor models, it's impossible to know exactly what you require.
In general, you can expect to have to fit and remove the engine and 'box at least half a dozen times before you get everything in the right place.
Hi Guest!
Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
