Alright so currently I am running two amps in my car, 1 of which is powering my single 12" sub and the other one is powering my 4 speakers.

Question is this...I have 4 gauge wire running to power 1 of them but can I buy one of those "splicers" things (cant remember the name) that you insert 4 gauge on one side and on the other side you can connect 2 single strands of 8 gauge will I be ok using that 8 gauge for both of my amps to power them.........?

The bass sub is pushing 750watts RMS at 2ohms and the 4 channel amp inst really pushing much cant remember but its no higher than i wanna say 50 watts rms per channel(4 channel amp).

 

It will work, but 8 guage will probably be a little small for the bass sub.

 

It depends on the length of the 8 AWG, whether it will be too small or not. Depending on efficiency of the amplifier, the max current draw would be between 80 and 120 amps (50% to 80% efficiency). For short distance, say under 24" the 8 AWG would be fine for this, also considering that this is a peak current value, not a constant current value, that will be on average much, much lower.

 

You're thinking of a distribution block

If your subwoofer amp is pushing 750W RMS and your speaker amp is pushing 200W RMS, I wouldn't run anything less than 2GA, preferably 0GA. I'm running 750W RMS between my sub amp and speakers, and I ran 4GA.

Like sixshooter said, if the power leads to your amps after the distribution block will be less than 24" 8GA will be fine. Be sure you use proper grounding as well.

 

I found this wiring chart a long time ago, but should give you a good idea of max rating for wiring: