[dsraven]

don't forget the power supply to an HEI is a 10ga wire so it needs a new fused circuit from the ign switch and the ign switch needs a good sized supply wire ran up to it as well. the system is only as good as it's weakest link. you could also run a relay close to the HEI supplied by larger ga wire and switched on/off by using the original small ga ign wire. use a good quality water resistant relay and fuse the power supply somewhere close to it's origin.
you will love an HEI dizzy compared to the points set up. do the whole swap though, dizzy, wire set, plugs etc.that would be the time to consider a high output coil, good wire set etc