I want to plug John over at Pony Carbs in Las Cruces,Nm. The web site is:[email protected] ,1-866-265-7669. He specializes in Ford style carbs such as the Autolite 1100, 2100 and 4100 series. After not being very satisfied with the 1850 series 600 Holley, and a 600 Cfm Edelbrock on my 5.0 equipped '63 Ranchero, I bought a 480 Cfm 4100 series carb on Ebay and sent it to Pony Carbs. For $249.00 plus parts, it was totally rebuilt, some of the passages were modified, and the throttle bores were re-bushed. Everything is polished with jewel like precision, the carbs are run tested, and shipped back with an installation video as well as full written instructions. The 4100 carb is the best carb ever made in my opinion. The Ranchero runs awesome!!! The throttle response is great, driveability is fantastic, and the mileage is at least 4-5 MPG better. He can also sell you one of his 4100 cores if you do not have one.