1968 GMC 250 motor won't stay running

[68gmcdude]

I have a '68 GMC with a 250 motor and 3 on the tree. I was driving the truck when it started surging. It would run good for 10 seconds then feel like it was starving for fuel for 10 seconds but it kept running. This went on for about 10 minutes or so. Whenever I accelerated hard it seemed fine with no missing or backfiring. After about a 1/2 hour of driving the truck just shut off. I coasted into a parking lot and eventually got it restarted. It ran for about a minute then quit running again. It did this 4 or 5 times until now it only runs for 5-10 seconds and quits. I ended up having it towed home. It's like it's starving for fuel. Could it be the fuel pump? Thanks!