new/old style body
depends on whether u have a new or old style body on your impulse, the older ones are just glued on and the newer are threaded and glued... you may need to soften the glue with something hot like a hair drier and twist if its new or just play with it till it drops off if its old and glue a new one in with a strong glue (locktite or suchlike)..... there are loads of aftermarket vertfeeds for the new (threaded) version, low and highrise so u should be able to pick one up easily, for the old (unthreaded) version, i assume you can only get them from SP.
K