Mike,

The DGV is allowed. The GCR lists about 5 optional carbs that cab be substituted for stock.
All are are Webers downdrafts except for the Holley 5200, which is basically the same thing.

Of course the Weber doesn't have the small "third-barrel" to feed the CVCC.
That is where I had to modify the mounting plates.

If you go with the Weber, I'd check to make sure the plates are designed for the CVCC.

Todd