Not sure about this wiring. When changing fron point distributor to HEI . Is there any reason the original power wire should not be used to power the HEI ,or should there be a heavier wire to run the HEI? Also this old heap had a six cylinder and now has a v-8 so far have used original wiring.

Yes,a very big reason.The oem wire is a resistor wire that will cut voltage to 8-9 volts.The HEI needs at least12.For a quick hookup run a 12 ga wire from the fuse box to the hei.There is a spot on the box marked ignition.Look under the FAQ section for a write up.

Here is one thread
http://67-72chevytrucks.com/vboard/showthread.php?t=180663&highlight=hei+wiring

Here is another.
http://67-72chevytrucks.com/vboard/showthread.php?t=13698

Thanks SMOKEKIKI: I Had a feeling there was something going on there with the wiring. Seemed I had read that not long ago. Had a couple of naps since then and just was not sure . Thanks for getting me back on track.. Larry

Everything you wanted to know is on this guys website. I re-ran the entire wiring system using his kits, for the price you cant beat the "full-power" kit. He takes all orders so you talk to him directly, I told him what I was doing and he shipped everything out the next day. This website is a great resource!
http://www.madelectrical.com/electricaltech/chevymain1.shtml

I have used them to on a couple of project, good stuff and it works