Need advice, 70 Mustang 428SCJ

[Musclerodz]

I never come on asking for advice but I am at a complete loss on this one. 70 Mustang 428 SCJ, all new all factory correct. Engine runs all day in shop. I go drive it and will die inside a mile. It will restart on prime but won't stay running. I have changed the fuel pump, have fuel pressure gauge on it and is not dropping fuel pressure, I have changed the coil as well, checked everything with the Holley carb. I have no restrictions I can find in the fuel system either. It acts like it running out of fuel. I have considered its either sucking air or vapor locking, only thing I have not done is rig up a temporary fuel pump. Any ideas.?