i have emailed John a few times and to be honest he is very helpful. i am planning on doing this at the moment and now i have just had my new +80 pstons delivered i can actually make a start on it.
to be honest the machining that is required is the same as what is needed for a 1275 except there may be a need to pocket the block.
after i have had the engine bored (might be an offset bore) i will know more with respect to the need for pockets or not. this conversion was first done on an 850 engine remember!!!
look here:
http://www.lojomo.com/I am going to run the throttle bodies and injection setup from the bmw head aswell. also have a look in my thread in the projects section for a few pics.