I replaced the Carter with 500cfm Edelbrock. Many moons ago but I don't remember any problems. Kickdown connection was a breeze. The main reason for change was because the Carter floats jammed on prolonged hard cornering such as motorway slip roads. The Edelbrock seems to have overcome this.

The only significant change was that the new carb top was too big for the original air filter so I went for an Edelbrock pancake. It wasn't simply a matter of making the hole bigger on the original as the bottom of the housing isn't flat.

I also opted for manual choke even though I never really had a problem with the previous bimetallic setup.