670 or 770cfm?

[moper]

I like them both..lol. But they both should get some attention. I find most DP carbs are dumping way too much fuel in. If someone's not good at tuning, the vaccum secondary keps them "out of trouble" easier, and is better in terms of economy and throttle response. But like was said, a double pumper can be tuned to out perform a VS.

[Chryco Psycho]

There's an old formula I use on street cars and it's
         
           engine cubes x max rpm divided by 3456

So 440cu X 6000rpm by 3456 = 764cfm

nothing personal but using the formula has never worked for me in the real world , I use ci X 2 as a starting point & with a modified engine lots more cfm