auto choke question

["Lishego, Michael" <MIKESL@tartan.sapc.edu>]

Hello to all fellow listers.  My '74 is about to undergo the drastic 
change from SU powered to Weber carbs this weekend.  The weber carb 
that I bought is an electric choke model.  There is a wire that exits 
from the choke on the carb, and runs to some place on the block.  
Where does this wire lead to?  Anyone with a similar carb who can 
tell me, I would really appreciate the info.  Along these lines, does 
the brake booster from later cars clear a weber?
Thanks in advance ~ Mike