1963 Chevy Truck Changed fuel line and fileter, won't start

I built a 305 with Edelbrock fuel pump, carb, manifold, etc. Have driven off & on for the last 7 years for about 4800 miles. Love the truck because it always starts 1st try. Decided to change my fuel lines due to fumes, and took the fuel filter from on top by the manifold to the other side of the fuel pump back by the tank. Put 3/8" fuel line, & had a lot of difficulty starting , and restarting the engine. so I moved the filter back to where it was with the same set up & 5/8" line ..still won't start. It did start once today by accident I guess - took it for a spin and it drove fine, turned it off for a few minutes, it started right up again so I thought it was fixed. Tried starting 3 hours later and it just cranks, tired another 4 hours later and just cranks. Haven't touched anything else..did I damage the fuel pump by placing the filter on the back side?