Here is a link that may help you find some parts.
There are a couple home brew things you can do to warm up your Olds yourself.
If you are knowledgeable about porting the heads, you could start there.
Since the compression ratio is probably down around 8.0:1, a little boost there wouldnt hurt at all. Maybe up to about 9.5:1.
A good free flowing dual exhaust would help a lot.
You might want to contact one of the older cam grinders like Isky, Erson, Clay Smith, Crane about a mild cam, or even regrinding your stock one for you.
The after market intakes would do wonders for your engine. I would go with about a 500 CFM Edelbrock or Holley 4 bbl.
In any event I wouldnt get real radical in building that engine. Its an antique and you want to take care of it.