Thank you for the compliments, gentlemen.

I decided on the Autolite 4100 because of the great driveability and reliability I received from my original Motorcraft 2150 carburetor my truck came stock with. When I converted to a 4-barrel, I originally used a Holley Avenger carburetor. It worked ok, but no matter how I tuned it, it never seemed to run as smooth as my original 2150. I later found out that Ford did offer a 4-barrel carburetor in the 1960s that was essentially a Motorcraft 2150 but with secondaries, and that was the Autolite 4100. That was all I needed to know. This carburetor is almost exactly like my original Motorcraft except for the secondaries in form and function. Even my stock fuel line from the fuel pump to the carburetor hooked right up with no modifications.

For street use and everyday driving, I found that the the Autolite 4100 (and Motorcraft 2150) are better carburetors than the Holley. The Autolite/Motorcraft thermostatic hot air choke works MUCH better than the electric choke found on any aftermarket carburetor, and Ford's annular boosters produce superior throttle response and economy over the Holley. And unlike the Holley, the Ford carburetor is a one-piece casting; it has no gaskets under the fuel level to leak. Best of all, my truck now starts up and runs every bit as good as ANY modern vehicle I have owned with fuel injection.

That small hose that you see connected to the top nipple of the PCV valve connects to the canister purge valve on the charcoal canister down by the battery. It's part of the evaporative (EVAP) emissions system. That particular hose connects to the top port of the canister purge valve, which provides the "purging" of trapped fuel vapors (from the gas tank and carburetor, which are also connected to the canister purge valve by hoses) from the charcoal canister to the PCV valve for burning in the intake manifold. It does the same thing that the bottom PCV valve hose does except that hose pulls vapors from the crankcase and into the intake manifold for burning.