[Darrell Ratchner]

Mr.mike and Rob, First I would like to preface this comment regarding due respect to all involved. Having said this my original comments were to express my experience in carb selection on dual quad setups for cobras. Let me state a few things.
1. What relevance does the flow rating on a 2v vs 4v have in this situation? Both carbs are rated on a different pressure drop but this just seems to confuse the issue.
2. I think it is pretty common knowledge that it is possible to use a larger vacuum secondary carb than a mechanical secondary one. This is due mostly to the fact that the engine air flow will govern when the secondaries open, not allowing the traditional bog or lack of response often associated with mechanical secondary carbs when open at too low of an RPM.
3. It is my opinion, which has been backed up by numerous articles over the years that all of the major manufacturers over carbuerated their High Performance engined cars in the 60's. The primary reason was NHRA rules which goverened drag racing in certain classes. Winning on Sunday sold cars on Monday. The manufacturers got away with the larger carbs by using vacuum secondary carbs for the street and allowed the stock class drag cars to fully utilize their potential. Remember that the drag racers go way past the RPM that a street car does.
4. Any serious drag racer will use a larger carb than would normally be used on a street car. Driveability is not a problem at the strip. They are looking for every last horsepower. A pressure drop of even 1.5" is too much. More correctly a serious drag racer would calculate his engine carb size by utilizing something near .5" pressure drop. Thusly you need a much larger carb.
5. My comments and recommendations were based upon a rather fool proof, inexpensive carb recommendation. The 450's are very streetable and require little tuning. Their small venturi size promotes excellent throttle response and driveability.
6. If your looking strictly for the exact LOOK of the original then the 450's are not the ticket. ie no vacuum secondary.

Now after pissing off half of the world I appoligize. Just trying to help. Darrell