Just a suggestion....give Tom Langdon of Stovebolt Engine Company a call...he's knowledgeable about the early GM's....I used his Holley/Weber progressive 2 bbl on my 54-235 and find it gives me improved performance, mileage, and ZERO problems, right out of the box.
The cost is in line with a rebuilt 1 bbl with none of the pitfalls. Give him a call.
Hope this helps.
