Help required

Dear all,
I'm using a transmitter and receiver pair placed on two arduino's to transmit data between them, but the data required to be sent is very large and unless the delay involved between two successive transmission is low ,it is not feasible to send the data. So i was wondering what is the min cycle time required for the receiver to interpret the transmitted data before accepting new data.

How large is "very large", what is the data rate, and what is the connection type between arduino and Rx or Tx device? (SPI, I2C, UART, software serial/equivalent)
Keep in mind Arduino can not do simultaneous tasks, so if it's busy responding to high speed data, it cannot at the same time process the data. If the data is not too fast, it can mix receiving and processing.

CrossRoads:
How large is "very large", what is the data rate, and what is the connection type between arduino and Rx or Tx device? (SPI, I2C, UART, software serial/equivalent)
Keep in mind Arduino can not do simultaneous tasks, so if it's busy responding to high speed data, it cannot at the same time process the data. If the data is not too fast, it can mix receiving and processing.

about 3KB in size , TX is connected to the digital pins and RX to the analog pins, i'm basically converting images into byte arrays and sending them using morse code,the receiving arduino does not process the data, its duty is just to print it on the serial monitor