Carbking would recommend exactly what Carter recommended so many years ago. Engineers REALLY do have a reason for what they do. Try the list in the link. I have posted it numerous times in various threads, but finally posted it on my website. This information was taken from the factory Carter records, of which I am the current caretaker.

http://www.thecarburetorshop.com/Carter_YF_Chevrolet.htm

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop