ok so i have a 72 cutlass with a 350. upgrading from coil to summit hei. cant i just take the power from the red wire that went to the coil? why dosent the hei have a ground wire?

 

The hei needs a full 12 volts to function properly. That red wire you talk about may or may not be deliverying 12v. Check it with a voltmeter to be sure. If you use the old points wire, it many only deliver 8-9 volts, which is all points require, the hei has to have more.

It doesn't need a ground wire because it is grounded through the distributor body its self. There is a little tab inside that grounds the coil to the body. You don't need to worry about that.