Just did 2 to 4 bbl swap car starts wont stay running please help

till then just advance it till it rattles(spark knock) when you stomp it and then back off a few degrees.It will run a lot better. With a cam and mods stock timing isnt optimum anyway.You can install a new plug in it and read the plug to tell how its burning by matching it to a chart on the internet. Google reading spark plugs.You dont even need a timing light.