275 was way under rated. That number was all buttoned up at the factory to meet the emission standards etc. and make the cars insurable. 275 at what RPM? Real numbers on these were 300-320.
Steve Dulcich rebuilt a '69 340 to factory stock specs including the stock 535 cfm carter carb and it dynode a max of 281 hp through manifolds.
he continued to add aftermarket pieces and a 750 carb alone jumped the hp to a little over 300.
i have no first hand dyno numbers myself,but with cam and other changes he ended up at 392hp
