[Dan Case]

From my notes file:

Three, as currently known, custom ordered new Cobras finished near the end of production (during 1965) received COBRA high rise aluminum intakes and Holley carburetors originally designed for 1965 MUSTANG GT350s, they were CSX2497, CSX2553, and CSX2555. All three received 1965 MUSTANG GT350 high rise intakes and carburetors AFTER 1965 MUSTANG GT350 production had started. These cars received manual choke knobs and operating cables in the instrument panel to the left of the steering wheel... CSX2497 was to date the only known Stage I Competition Cobra sold new that way.

(Side note. CSX2513, one of the sixteen special competition Cobras with 'cut back' doors was “sold” as a used car to Shelby’s driving school 12/18/64 with a used “Mustang” engine with a high rise intake and 1964½ Ford 427 C4AF-9510-DA revision level A dated 4B4, R-2919 Holley carburetor but that race only car is not in the count above.)

There was another very rare COBRA “high rise” intake manifold not intended for street use that I have found zero evidence that Shelby American ever installed in any new car. I have only seen five of these intakes and have owned two of them. Three of them had been broken and welded up as a repair at some point in time. They are very light weight thin wall castings and they are fragile if any fasteners were over tightened. I have a new old stock one that the original owner of a CSX23xx range car bought over the dealer's counter for his new Cobra but he never installed it. The latest one to come to my attention was dealer installed in a CSX24xx range car and it appears to have never been messed with since that installation but the Holley carburetor was separated from the car just before the current owner bought the car.

All three cars described above 'lost' those factory installed induction systems over time. When the owner of CSX2555 had the engine modified during a restoration he had the 1-4V induction system replaced with a Ford / Holley 2-4V system of the type used on Trans Am Mustangs in 1967 installed and I got the R-3259 carburetor dated 4B5. (The sign off date on the original specifications for the R-3259A was December 2, 1964. Holley had two production runs of them in December 1964 in time for the start of GT350 production. In more modern times a subsequent owner of CSX2555 had car returned to a more day one like configuration. I offered to sell him the car's original carburetor at the cost I paid for it years before. He was not interested. Later I sold the carburetor to the owner of 1965 MUSTANG GT350 SFM5026 which was complete in the old Cobra works at Venice and not the new LAX shop like most 1965 GT350s. Early in 1965 a metering block change occurred and to Holley they became R-3259AAS models. The next change altered timing and rate of opening of the secondaries and became the R-3259-1A. The final model going to Ford was the R-3259-1AAS with a different main body casting as the easy to spot difference.)

The R-3259/R-3259-1 family of carburetors (under Holley revision levels R-3259A, R-3259AAS, R-3259-1A, and R3259-1AAS) can be tuned to work very well in an original Cobra but do poorly if tuned like designed for Mustang chassis. The angles at which engines are installed in chassis are significantly different between Mustangs and Cobras. The short wheel base and stiff suspension of Cobras also affects performance.