Well, the two barrel set-up I'm getting ready to install doesn't really have provisions for charcoal canisters or EGR, so in preparation, I decided to go ahead and remove them before I take the one barrel (Holley 1945) off. I figured that way I'll be changing as little as possible at one time and keep myself from running in circles when/if I end up troubleshooting problems.

The EGR system was easy enough; all I had to do was remove all the hoses going to the carb and cap the ports. I understand (most of) the theory behind the operation of the charcoal canisters, but I just wanted to check for clarification on a couple of points. It seems their are three main "Input/Output" hoses: the vent from the carb, the vapor return to the carb, and the line from the tank. The way I understand it, the line from the tank and the vent are "inputs," and line vapor return line is the "output." I believe all the others are simply "controls." It doesn't seem that simply capping the vapor return and control lines and connecting the other two together wouldn't really accomplish a whole lot.

I'm trying to avoid just venting these lines directly to the air, mainly because I don't want the gas smell in the engine compartment. My first inclination is to try somehow venting them back to the tank. If I understand correctly, the hose which comes off the side of the fuel filter (mine has three), is designed for just this purpose. Is there any reason I can't just use a T-fitting and divert the two lines I know have remaining into this return line? I believe the fuel cap should have provisions to vent the excess pressure, should any arise.

You really ought to run a charcoal canister; it does not negatively impact performance and, when in proper working order, really cuts down on the gassy smell and saves you fuel, too. Even if you're running some kind of pre-1972 carburetor that doesn't have a ducted float bowl vent, you can still run the charcoal canister for fuel tank venting purposes (in fact, there's scarcely any other safe and effective way to vent a fuel tank originally intended for use with a canister).

The original canister you've got is probably dead by now. Fortunately, they are all rather universal. Get one with a purge control valve (little round plastic "flying saucer" looking dingus) atop it, and install a new canister inlet air filter on the bottom. If your carb hasn't got a ducted bowl vent, cap off the "CARB" or "BOWL" fitting. Connect the "TANK" fitting to the line from the tank. Connect the "PURGE" fitting via a tee into the PCV hose. Connect the small diameter purge control line via a tee into the distributor vacuum advance hose.

There needs to be a canister purge valve that only opens when the engine is above idle. Some canisters have these built in (looks like a round "flying saucer" atop the canister itself), but many do not, including Mopars after '72 and most late-model ones in which purging is controlled by the computer via a solenoid. Fortunately, standalone purge valves are readily available. NAPA Echlin # 2-28011:



Small fitting gets teed to the vacuum advance hose (which should have no vacuum at idle, full vacuum above idle)

Big fittings go inline with "PURGE" hose from canister to PCV hose.

The reason there's no purge valve on most of the Mopar canisters is that the "purge" port on the original-equipment carburetors were set up so as not to have vacuum at engine idle.

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