340 has no balls

This car seems to be hard to start like the gas has drained back from the line in the manual fuel pump .When I had the clear fuel filter I saw non full filter and thought about that .Once warmed up car seems to cruise ok infact I had it on the highway going 75 or so.it will take it but not all at once. Hard on the gas makes it rattle. Well, thats the story as I see it so far. I will be checking the timing . Its probably got too much .Is 5 degBTDC the correct setting ?? Oh and im not in a big hurry to yank that matching 340 from the dart . I know they are sweet. the 408 is an Idea but more of a last straw.im sure ill have more questions