NEVER put a 750 on a 318........
You can run a big carb on a small cube engine if it's a Carter/Edelbrock or a Holley vac. secondary, or a Thermoquad. Your stock Teen may not like a 850 double pumper, dual inlet Holley with 50 cc Reo pumps. Now take the dual quads for instance, you run off of 2 or 4 barrels depending on your linkage on the dual quads. I don't know the specs, but the primaries of a 600 cfm carb are 300cfm or less. Even if your linkage is not progressive, a teen should be able to handle 600 cfm. Kick the secondary's in and the air valves will only give the engine what it needs. The 6 packs run off the center 2 barrel. Depending on which set up, they are what 390 cfm? The outboard carbs are vacuum operated so they only give the engine what it needs as well but you guys know all this. It's like preaching to the choir! LOL