[Ed Wright]

For years I ran two of those things on my ‘56.
The rear float has a notch in the bottom to clear the rear “secondary” throttle shaft. I ran a rear float (with that notch) in the front, also. More fuel in the bowl. When we went to Super Stock, with big camshafts, I began to see dark spark plugs.
Pulled my head out, decided my primary metering rods were not down where they belonged at idle, and on the return road. A wooden match stick standing on the metering rod
piston so I could see how the piston & rods were responding.
I first clipped the springs, but found it lean going down the track. Metering rods not rising enough at low vacuum/Wide Open.
I tweaked that linkage to manually raise the rods to the smallest/Power step on the rods.
I finally worked on the profile on the plastic meteor rod “cam”.
The carb Pros may have slicker ways, but I set records, and won races like that. No expense.
I messed with weaker springs under the P.E. Piston, but never found what I needed at both Sea Level & Altitude tracks. Lower manifold vacuum is effected enough with low Baro values at higher elevations caused caused issues with weaker metering piston springs. Thus I went to raising it manually.
Hope this helps somebody.