Time to Fix It Right

Assuming the engine has good compression, my first looks are at carb, dist., and gas tank!!!! Has the tank been off and cleaned ever?
A new Edelbrock would be a good investment.
I have had many issues with old distributors. Maybe a re curved one for your setup?
Like said above, these mechanical wonders need to be driven regularly!!!! Man problems will develop when not taken out to stretch their legs. And open them up too!!!!!