Crowd carried east for large rally (8)
I believe the answer is:
jamboree
'large rally' is the definition.
(I've seen this before)
'crowd carried east' is the wordplay.
'crowd' becomes 'jam' (jam is a kind of crowd).
'carried' becomes 'bore' (I've seen this before).
'east' becomes 'e' ('E' can be a synonym of 'east').
'jam'+'bore'+'e'='JAMBOREE'
'for' acts as a link.
(Other definitions for jamboree that I've seen before include "Lavish celebration" , "Boy Scouts' international gathering" , "Scout gathering; big party" , "Party - gathering of Scouts" , "Scout 1 across" .)