[rotorwrench]

Ford was in with Holley clear back before the Model T era as a supplier of parts. Henry Ford made deals with them for manufacture of Holley designs in the early V8 years. When Ford decided to use the Holley Load-O-Matic designs in the 8BA era, that carried through on into the early Y-block years which affected both carburetion and ignition for spark control. With the larger engines coming on line in 1957, this finally signaled a change in ignition systems to better control the spark for higher performance engines that were in demand. Using the new type distributor with mechanical advance and vacuum load control required a change to carburetion as well. The new designs were develoved to work with the newer MEL and FE engines that were coming on line or in development at the time so it makes sense that the 4150 would show up in that time frame. Ford wanted to build there own stuff so the 2100 2V and 4100 4V carbs were developed so that Ford could save some bucks & make their own carbs as well but the Holley 4150 was used for most special performance applications well after that.

GM gravitated toward the Rochester carbs with some Carter carbs and Mopar used a lot of Carter carbs but Holley carbs were generally preferred for special high performance applications by most manufacturers when they wanted top performance. The modular design allowed for easy changes on the fly. It was a lot easier to tune an engine for different altitudes if you had a Holley 4150.