Starting issues

Having a problem with my 73, I had and exhaust leak. Was suprised that I was missing some exhaust manifold bolts. I replaced the bolts no more leaks but I am having a problem starting. The car turns over but does not stay running, I have to keep on the gas a then it dies after 5 seconds. I thought it was a fuel pump issue so I replaced it along with the fuel filter but the same problem. I just bought the car not too long ago so I already replaced the distributor, plugs, coil, battery, regulator, starter solenoid. It was driving up until I closed up the exhaust leak. Not sure if that was a coincidence. Any ideas would be appreciated. It seems like a fuel issue but not sure if closing up the exhaust caused some vacuum issues, not really sure.

I would check for voltage at the coil with the key on. You may have inadvertently pulled the connector that supplies voltage during run condition. When the car is cranking there is a separate circuit activated, but it cuts off ass soon as you release the key.

If voltage is good, I would check for fuel flow. Does the accelerator pump squirt when you give it gas? Fuel filters are generally direction specific-is it in backwards? Is your fuel pump plumbed properly (I put one together backwards and filled the carb's fuel bowls. It ran a moment and then died as the pump sucked the fuel out.) When you installed the fuel pump did you verify proper installation? (Crank and make sure it is pumping fuel before hooking up carb?

If you have voltage and basic fuel flow, then I would look for a massive vacuum leak.

if the only thing you did was correct the exhaust leak then its a possibility that the exhaust system is plugged.

Also check vacuum lines for any leaks, holes in old rubber lines or disconnected.