A few comments about exhaust smell versus how the engine is running...
First, exhaust smell is not an indication of how rich or lean an engine is running - there are a lot more factors involved in how your exhaust smells, including camshaft duration/overlap and ignition timing (none of which will be solved by fuel injection).
A rich engine will run high on CO, and CO is odorless... On the other hand, HC can be smelled, and HC is caused by ignition and timing issues. In fact, if you're too lean, you will get excessive exhaust smell from a partial lean misfire that is often not audibly detectable. Without a wideband ox sensor with an A/F readout, you cannot tell how rich or lean you are - you sure can't tell by smell, so I would not assume you are running rich just due to the exhaust smell.
If I were you, here's what I would do:
First make darned sure your timing is set right so you have 36 degrees total timing and about 12-18 degrees of initial. Make sure your vacuum advance does not pull in any more than 16 degrees of additional timing - modern fuels won't take that much timing lead without causing misfire (which you'd be able to smell). Put a slot limit in your vacuum advance slot if you need to in order to get the vacuum advance down below 16 degrees.
Once timing has been set up correctly and verified, set your idle rpm to about 750-800 and start with your idle mixture screws at about 4-6 turns out from lightly seated. Turn them both in 1/2 turn at a time until you get a 50 rpm drop in idle speed. At this point, your A/F mixture will be about 15:1, which is a tad too lean for ethanol-added fuel, so crank the screws back out about 1/2 turn from that point. This will get you right about at 14:1 on your idle mixture, which is perfect.
If the idle mixture screws do not respond, or if you can screw both screws in until they bottom out without the engine killing, you have other carb problems with fuel entering the manifold from the wrong source. If the engine runs with both screws bottomed out, observe the booster venturies and see if you have fuel dribbling out of the main discharge nozzles - this should not be happening at idle, and is indicative of other carb problems which would create a rich condition or a rich misfire, which could be smelled.
Lars
