For those worried about hood clearance there's a part you can try that might provide that extra little bit of room. If you have a 4150 carb and a 14" air cleaner, go to the Chevrolet dealer and order part #6422188 - it's a drop base originally designed for mid '60s Chevrolet muscle cars with the 780 Holley. It drops about an inch lower than any aftermarket drop base you can find.