Truck won't stay running!

[woodman13]

I am trying to get my new 1969 project truck running. It will run for a short time when cranked up then dies. It is a 350 with 11.0-1 pistons, has a holley 750 DP, a g team intake, a MSD billit standard dist, headers, solid cam that sounds big, dart heads, roller tip rockers, 6AL MSD box, mechanical holley fuel pump, fuel cell in the bed, 2800 stall, T350 trans. I put new plugs in it, made sure it was getting fuel(it has a clear filter by the carb). It did backfire thru the carb when I tryed to start it then it started and ran and died. There is no timing tab on the engine, so I don't know about the timing or how it is set up. But with it starting and running for 10 seconds so I think the timing is close enough to run. Any ideas of something I should check would be great.