You said your distribution block has one 4 AWG input and four 8 AWG outputs, right? If so, as long as you are not running any other amps, hook up two 8 AWG wires to each amp, but make sure you put the bigger fuse in like SPL said, and make sure you use either 4 AWG or two 8 AWG groun wire.
"Anyone who has never made a mistake has never tried anything new." -Albert Einstein