ok art , grab our viewing glasses , pencil and pad of paper , lol
main harness connector at firewall
bolt that holds the engine harness to the interior harness , you need to undo the bolt and pull the harness from the interior connector
then you will have this , when you pull and flip the connector , and you can see the male spades
here is the male spade outside of the connector , you can see the right side(in the pic) is not attached at the base , this is the locking tab that holds the spade in the connector , use a screw driver or something to bend the end towards the center , then pull the wire from the harness side
in the case to go with this post , the resistance wire has a braided sleeve , where the regular wires use a plastic sleeve , so its easy to spot , now any factory equipped GM vehicle with a HEI from the 70's to mid 80's all use the same spade terminals , so finding 1 at the junk yard shouldnt be to hard
just cut open the stock harness from the donor vehicle , and pull the large red wire for the HEI out of the harness , and in similar fashion to the pics above pull the male spade from the connector
then use a screw driver or similar to pry the lock tab back out some , so that when you insert it into the conector for your car , then run the wire with the factory wires to the dist , and plug in
now this will work for any of the wires , i rebuilt the fire fried harness in my 68 elco , as well as added the large red wire for the HEI to run my MSD box
cutting and using a regular butt connector might be easier , but will cause issues down the road , even GM and chrysler use heat shrink style butt connectors , which will provide a sealed connection as well as making it more vibration resistant
but why cut and splice , and add possible issues down the road when you can add a good solid wire from point A to B
hope this helps alot of you out there