If you want to raise the front end, you are going to have to go to heavier springs than what came with the car. You need a spring catalog (or a knowlegeable sales person-or maybe talk to someone at a spring shop) to get a heavier spring, say out of a Chevelle station wagon of that period with a big block and A/C.
Custom springs can be made or ordered through a reputable spring shop. You can also use spacers (not the kind that go between the coils) that look like pads and the spring rests on them.
Heating a coil spring (a definate no-no as it weakens/fatigues the metal) will actually lower the car. If you put a custom set on and she stands too high, you use a cut off tool and take off a quarter of single coil until you arrive at the desired trim height.
Now once you have achieved the height/look that you desire, the front end geometry will have been changed. You have to consider shock travel and bump steer. All of this can be compensated for by a knowledgeable front end tech.
The cheap way out is to find an Olds or Cad in a salvage yard and measure spring diameter. Get a set that will fit in your spring pockets.
I would go with a custom set as it will cause you a lot less headache.
Don't forget to install new spring pads and whatever else is worn while you are there and you should do fine.