Testing fuel system

i can tell you now , that i would have already ditched the 625 for a holley 750 DP. and i would have already installed an electric pump regulated at 6 . i think you are just plain running out of carburetor AND fuel pressure. thats my opinion

+1 on this....my 318 has a 650 on it, with a decent cam and it is just right for what i need.