slant six timing

If it's completely stock, try an initial timing setting of 5° BTDC (engine idling at 700 rpm). You will want to bypass your OSAC valve -- that's the widget on the passenger side of the firewall, with one hose to the carburetor and one hose to the distributor. Simply take the OSAC valve out of that line by connecting the hose directly from distributor to carburetor (same port on the carburetor). Don't worry about total timing until you go all-in for a distributor recurve—then talk to DusterIdiot over on slantsix.org about it.