Never personally owned a 280C. Knew two people who had and both replaced the stock Solex 4-bbl carb with a Holly (there is/are Holly conversion kits available - JAM engineering (advertise in STAR) should have them). Once done, both cars were very nice drivers. I have lost contact with both so I don't know what current status is. I knew them for over 3 years and, as far as I can remember, they never had any serious problems with the 280C. I have a 250C w/dual Zeniths which I replaced w/Webers and now the 250C is a very nice car to drive. Personally, if the rest of the car is in great shape and you want to pop for a Holly conversion (don't know the cost - my Weber conversion (2 carbs) and kit was $550.00 three years ago) I would think you would have a very nice driving 280C. Just my opinion and 2 cents.
Dan Taylor/ Tulsa, OK MBCA '71 250C/'81 300TD-T