holley carb guru's

I recently bought a 1966 valiant slant with a 4 bbl carb-- well the prior owner JB welded one of the secondary venturi's.

Holley 390 4 bbl-- will get numbers later.

1. can anyone replace just this item?
2. is the carb now a junk carb
3. is there any adhesive that will with stand this bond?
4. anyone have a 390 cfm carb for cheap?
thanks Lawrence