An Edelbrock 1406 is a 600 cfm 4 barrel carburetor - a bit much for an otherwise stock 292 engine, in my opinion.
The 292, in stock form, has too little compression, too little cam and too little displacement to adequately use a 600 cfm carb efficiently. To get best tuning you'd have to probably have to drop your float, and certainly change your metering rods and primary jets to something smaller.
For a 292 that is stock other than intake and headers I recommend a 390-450 cfm 4 barrel, available from Holley. You should be able to get optimum power and mileage with minimum changes. Anything larger would be fuel wasteful and power robbing.
If you do some port and polish work on the head, get a higher performance ignition, and go with a mild performance cam that bumps the maximum powerband up 1500-2000 RPM over stock then a 500-600 cfm carb will probably work just fine.
-magic mike-
