We need more information...please.

For goodness sake if you have or had an original running engine and Hydramatic transmission, don't make changes now. It's like putting the cart before the horse. The absolute best carburetor is the one that came with the engine-transmission combination. I skimmed your past postings and didn't see anything about what you have other that a 1954 GMC plus your handle includes Hydramatic. I hope you took pictures and made notes of the shifter and throttle linkages before you pulled the engine. It will be agonizing to get it right again. Very few here can help guide you to get "Humpty-Dumpty" back together again and working correctly. If you plan to use another type transmission then please forgive my panic-ranting.

"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."