Curt - Chrvrolet used a 2GC on the 265. Also, a number of V-6's in the 1970's used the 2-GC. In this case, smaller is better.

Adapter height??? Why use one??? First pick the carbs you are going to use and then FABRICATE A MANIFOLD TO FIT!!

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