I bought an early 74 260z with flat top Su Carbs,I had a 73 240z but sold it because of its condition. The 73 had dual webbers, that ran well and i learned to tune and adjust them. The 260z that i have now has been stored since 1996 in a garage. It is all stock with flat top carbs and the P.O told me in order to start car I need to put drops of fuel into carbs. I went ahead to change into a 5 speed transmission from an 83 280zx and a CLSD 3.70, this motivated me to find some earlier type round top SU's. I never turned the car on with the flat top carbs. The round top Su conversion was fairly simple, I kept my n36 intake and switched balance tubes from the early carbs. I blocked unnecessary lines and hooked up fuel lines and booster vacuum line. I finished everything within a couple of days, now it was time to start the car. I tried to start the car with staring fluid and it ran for 2 seconds. I did this for 10 times till i gave up. I went ahead and did research. I checked my mechanical fuel pump and the lines from electrical fuel pump to mechanical pump were dry. I hooked the line back up and removed the valve cover and pumped the mechanical pump using my hands. I did this for a total of 10 minutes and no fuel coming out of line. I then tried another method of adding fuel to bowls and hoping the mechanical pump will start to pump. The car ran for a total of 5 minutes till it died. I checked the line from tank to mechanical pump and it was still dry. I filled the bowls again and it ran for another 5 minutes, I tried to rev car but it dies down. I then go back to mechanical pump and its still dry. I changed the fuel filter just 2 days ago before start attempt, and fuel is getting to filter. I am assuming the fuel lines are clogged or the mechanical pump or electrical pump are not working. I not sure what to do now and why is the car bogging out?