Stock rockers are 1.5 raio in a 350 chevy motor (they vary a little in the stamping process), the push rod length is 7.800", I think. I wouldn't recomend changing ratio's on a stock motor, machine work to the heads is "sometimes" required to clear the pushrods where they pass through the casting. Push rod lenght does little for performance other than relocating the contact position of the rocker to the tip of the valve. If you wanted to add perfomance parts it should have been a consideration during the rebuild process. Just my 2 cents worth though. Good luck!