[Dan Case]

List 3259 / 3259-1 Holley (700 or 715 c.f.m. depending on which reference you come across)
Great carburetors but not for everyone as they are not easy to get working float levels figured out for applications besides 1965-67 Mustangs. I have worked on many of them for pure stock to 8,500 rpm max effort (never had a fuel delivery problem) engines. The only modifications that I found that made a positive (improve performance at anything close to my 600 feet above sea level location) difference were revised float levels and the timing of the vacuum secondaries.

On an original leaf spring Cobra they just about will not work with the GT350 designed float settings listed in the Holley Variable Specifications Manual. With floats set like a GT350 the carburetors will dribble fuel after the engine is shut down, dribble fuel on any grade any direction, have rich stumble on rough road, rich stumble on hard cornering, surge at cruise, flood the engine out on hard braking, and make hot starts very embarrassing...like a worn out mid 1960s Dodge.

Their Ford applications cousins are the List 2919 for 1964½ 427 High Riser race engines and listed as optional for racing Cobras, Sunbeam Tigers, and 1965 MUSTANG GT350s. The R-2919 is also listed as the racing carburetor for 427 Cobra competition cars. The List 2953 which I think was a 427 SOHC crate engine model. The List 3255 for 1965 427 MR crate engines I believe. And the List 3255-1 as used by some late 427 4V Cobras. I prepared an R-3255 or R-3255-1 (those notes are long gone) for 427 Cobra (I think it was CSX3011.) just before a Bahamas vintage race. It was sent to me because the restoration shop could not get the car out of its own way. They bought the carburetor at high dollars from a national carburetor restorer. I detailed the operation of the carburetor, changed the float levels and tuned the secondary open to what I thought the car might handle. The shop and owner were very happy with the results. I believe the car won its first race with this custom set up carburetor.

Dan