Timing for a 318
Oh yeah, Also check to make sure that your vacuum advance for the distributor is connected properly. It should be connected to PORTED VACUUM, not MANIFOLD VACUUM. There is a difference and many people don't know and connect it improperly. The vacuum hose from the distributor vacuum can should be connected to an upper vacuum port on the carburetor, not the lower ports coming out of the carburetor base or a vacuum tee fitting on the intake manifold.
Ported vacuum has no vacuum at idle and then gets some after the throttle is opened. If you are not sure put a vacuum gage on the port and make sure there is no vacuum at idle and then some when you increase engine speed. If you connect it to manifold vacuum, you will have all of your vacuum advance coming in at idle, not under load like it is supposed to. On a Holley the ported vacuum is the one coming off of the metering block for the primary side of the carburetor. On Carter/Edelbrock it is one coming off of the main body of the carburetor, not the base and is higher than the base plate for the carburetor.