Carter used a spring-loaded fuel valve in the YF carbs built for Chevrolet, with an orifice of about .081.
Carter used a standard fuel valve in the YF carbs built for the Ford 300 CID with an orifice of about .101.
When your FLAPS still did a decent business in carburetor rebuilding kits some 30 years or so ago, out of a hundred YF kits sold, they sold maybe 99 kits for Ford, and 1 for Chevrolet (remember, the YF is aftermarket for Chevrolet). Since "one size fits all", guess which fuel valve comes in the FLAPS kit?
If you got a kit from us, or if someone else makes a kit with the correct spring-loaded valve of which I am unaware, which you acquired; the float adjustment with the spring-loaded valve is made with the weight of the float resting (NOT pushed down with your finger) on the fuel valve.
Inline dial-style regulators with no bypass, and no return line are quite useful if you have a strong right arm (or left) and a rabbit problem in your garden!
For a fuel regulator to work properly, it requires a bypass with a return line.
Jon
