I find these wiring diagrams very helpful.
http://www.ebay.com/itm/1970-70-Pont...hWXarb&vxp=mtr
With all the modifications that have been made to your harness and its age you might want to consider getting a new engine compartment harness that is set up for HEI. If i'm not mistaken the stock wiring harness has a resistor wire in the harness for the points ignition system and will not provide a full 12 volts to your distributor.
http://www.ebay.com/itm/HEI-engine-w...lTo5bS&vxp=mtr