68 340 4-speed distributor

The only non-vacuum ones I'm aware of are some industrial/ marine, and maybe some "race" pieces. Certainly EVERYTHING that was sold through a dealer as a licensed passenger car had vacuum

Remember---68 was the first year of FEDERAL (not just CA) engine emission controls. GM "did" this with a smog pump. Chrysler "met" the regulations with leaned carbs and modified advance curves, etc etc