I can try the fuel pressure regulator. I was told that 9-10 psi would be fine on a Holley but I have a Holley Black fuel pump i'm going to put on the car, so I'll put a fuel pressure regulator on then.

The stock springs and weights are in the distributor. I replaced the rubber hose to the vacuum advance but i'll check the canister. My neighbor who drag races a 68 Chevelle with a 400 small block/ th350 said that what he did on his car was cut the vacuum canister off and welded the rod where it was.

I should note that when the motor was on the dyno, and in the car for a couple hundred miles, the vacuum canister wasn't hooked up to a full vacuum port. When it started running rough, I timed the motor, and hooked up the vacuum canister to a full vacuum port. That should only affect mileage though right?