86 F350 460 fuel problems
 

I have an 86 F350 that starts up and idles for about 45 seconds then dies like it is out of gas. This is on both the front and rear tanks. Both tanks have fuel, the inertia switch works, fuel filter at the carb is new and no fuses blown. I removed the tank transfer switch and it is not plugged and both tanks flow gas to the switch. The oil pressure gauge also works. If I let set for a while and then start it it will run for a short time then dies. If I try to rev it up as soon as I start it it only runs for a few seconds then dies. I need help.