Carburetor cfm for a mild 318 build

I'd have a custom cam cut for that with your goals in mind. YOu have a low compression, small valve engine with specific goals. A cookie cutter cam isn't going to be your best option.

Gearing is so subjective and dependent on other factors. I run 4.56's with an OD. Worked great with my old engine, works like crap with my new engine.

IN regards to converter, you need to know the specs of the car and the engine, anything else is guessing and a waste of good money.