How many CFM for my 340?

Thanks for the reply......

The 650 CFM was a mental typo. Thanks for correcting me. The 1405 Edelbrock is a 600 CFM. I'm planning to put a 1407 (750 CFM) on the Edelbrock Performer RPM, which I believe is a dual plane intake, but a thermoquad (spread bore) won't fit that manifold without some kind of adapter.......

The car is a street muscle car. No racing. It has an over drive 4 speed. The 8-3/4 rear is a 3.58:1, but will be swapped with a 3.91:1, clutch type Sure-Grip, shortly...

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