Bornco,
Can you post pictures of what is broken on your carb? May help in deciding if repairable or requires replacement.
On another note (similar to "bouymaker"), do a search on ebay for "1966 Rochester 4 jet carb".
Right now, there are at least 2 4GC carbs with manual choke listed for sale (1 for $100 which pictures show exact match for "7027125" and another for $75 listed for parts only but picture shows manual choke setup).
Hope this may be of some help.

Dan