2 6 pins worked perfectly. I went back and re-did the connections with the 1300w PSU and forcing 8 pins into the connectors was what caused it to not power up. As soon as I used 6 pins they worked great.
SMH...
Did you bother to look at the PCIe pin out or did you just solder your +12v to the top 4 wires? You're lucky you didn't short out your PSU.
It didn't power up because 8 Pin PCIe has the same number of +12v lines as 6 Pin PCIe, (3).
It has 2 extra GND wires instead of +12v & GND. 8 Pin EPS on the other hand, that has (4) +12v & (4) GND.
I don't know what wattage you are working at, but also bear in mind that 6 pin PCIe is only rated for a conservative 75w. You could likely go to 125w before exceeding the pin rating, but be sure your wires that are feeding the pins are at least 18AWG. 22AWG, which is common on some of the cheaper connectors will melt.