Not as simple as I thought. I got these instructions with a RTE IVR3 solid state voltage limiter. So you need their limiter, or a constant 5V source and the pictured resistor to read full scale.
https://rt-eng.com/index.php/RTE_limiter.html
4 7/32 ID is the right size for early AFB's. I might have an original base, will check tomorrow. Or you can find a standard base and cut the outer diameter to the filter pad. That 4 7/32 ID is used on most AFB's up to 1967 and larger 2 barrel carbs on big blocks.
Complete 273 minus intake manifold, exhaust manifolds, distributor, and solid rocker gear. Ran very well, double roller timing set and recent valve job on a set of 675 heads. Just getting ready to swap in a 57 Desoto 341 Hemi.