Is it ok to use a 800 cca battery if the specs call for battery?

No, it is not okay to use a 800 CCA battery if the specifications call for a different CCA rating. The CCA (Cold Cranking Amps) rating indicates the battery's ability to deliver a certain amount of current at 0°F (-17.8°C) for 30 seconds. Using a battery with a CCA rating that is too low for your vehicle can result in difficulty starting the engine, especially in cold weather or when the battery is not fully charged. It is important to use a battery that meets or exceeds the CCA rating specified in your vehicle's owner's manual.