I have a 68 Cutlass Supreme with 350 Rocket. It has an Edelbrock intake and 650 carb. It was running well until about a couple weeks ago. It has started to idle rough and also miss at idle. Yesterday the car died after I started it but fired right up after that. Not sure what is going on here. Any suggestions? I looked all the vacuum lines and they are all connected? It runs smooth when I am accelerating...except it starts to surge once I get to 40-50mph accelerating heavily. Then I need to let go of gas and accelerate soft and it drives fine. Get 40psi oil pressure at idle and 60 when driving.

 

Did you flex the vac hoses around the connections looking for cracks there? Vacuum caps often break at the top. Carb still secure to the manifold? Plug wire come loose? Crappy gas?

 

I would also replace the fuel filter, could be clogged. For like 3 bucks its worth it anyway.

 

When was the last time it was tuned? Points or Electronic ignition? Miles on engine?