Guys I'm not trying to start a war.

52carl, https://quadrajetparts.com/ethanol-rated-pump-diaphragm-assembly-p-2943.html
Carter YF 2100S Pump Diaphragm Assembly part number is 203-60S
If you have doubts, give them a call and let us know what Ethanol resistant material is used.

From my memory, from past comments here, is that the Daytona UN2 (Zenith clone) is okay for 216 and 235 but is full throttle lacking on a 261.
The UN2 longevity PROOF (not just, it has worked for me) is unknown compared to Carter YF which has been around 60+ years and is still working.
Be warned there is another Asian made Zenith clone that is junk.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."