Take the headache out of trying to make a Rochester B work.
Carter's replacement carburetor for that time period:
Carter YF 966s 1950-52 235 but will work decently on your 54
Carter YF2100S 1950-56 235

I posted a 966S link in the "ebay and craigslist" section that sold for $18.25 + shipping.

"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."