Engine starves for fuel?

Hi I have a 1967 Satellite with a 383 stock engine, compression good in all cylinders, The carburetor has been recently rebuilt by a mechanic that has worked on carburetors for the past 25 years. The spark plugs are all new including wires and cap etc. Until recently the engine has responded perfectly when pushed. It has an automatic 727 transmission with shift kit.  Now when i kick down the gas pedal it responds directly for the first few seconds then it looses power, the car idles well and runs perfect when not under load. I replaced the fuel filter at the engine and made sure the air filter was clean. The fuel line that runs from the fuel pump starts in steel then someone in the past changed the line from the fuel filter to the carburetor to neoprene, i am not sure if this could have an effect. Any advise would be appreciated. Ive also noticed that if i push the gas petal steadily to the floor the car responds well with no hesitation, only when i directly floor it is there a problem and as it increases the rpm it lurches. Pete  

the first thing i would do is a full flow fuel pump test....

disable the ignition ... this means... unhook the coil primary wiring.. so there can be NO SPARK...

disconnect the fuel line at the carb....   extend the open end of the line into a gallon plastic bottle...

2 liter soda bottles will also work...

have someone crank the motor for 10 seconds while you watch the pulses of fuel into the bottle...

you should have full pulses into the bottle...  each pulse the same .   and you should get one pint in 10 seconds...

if the pulses of fuel get smaller with each pulse... you have a blocked fuel line.. a crimped fuel line.. a dirty filter... a dirty strainer in the tank...

you could also have a hole in the strainer... and its pickup air...

i have found fuel lines so restricted.. that i could pull vacuum on them with a brake bleeder hand pump..


after you verify the fuel flow is NOT RESTRICTED>.....

what kind of carb do you have????

the last thing... what kind of ignition system do you have....  have you converted to a MOPAR factory type of electronic ignition...    i have seen high mileage units break the pick up coil wires from the vacuum advance moving the breaker plate..  

I will test the fuel pump as described. The carburetor is carter afb. The ignition system is original but was working perfectly until just a few days ago. If the fuel pump is fine i will change the ignition as recommended. thanks for the advise so far Pete