Fuel starvation problems!

Just figured I'd run this one by you guys here,too. Here's the problem the same as I also posted on the IFSJA web site:

OK,here's what I've got:
1983 Chero,360,auto,MC carb.

This is my problem:

I was having the dreaded vapor lock problems,so I switched to an electric fuel pump,this cured my ailments,until recently(approx. 3 mos. since pump swap). Now it's acting like it's running out of gas,kind of like it's just not pumping the fuel fast enough to feed the engine's needs under power. It seems to run fine if I just putter around like Granny,but if I take it out on the expressway,it starts up with the starvation problems. I originally thought it was the pump's pre-filter clogging up,so I swapped it for a fresh one with no improvement. Then I thought it was the cheap-o Auto Zone electric pump I put on it,so I went out and bought a Holley "Red" electric pump. Put it on with yet another new pre-filter,and still the same ol' thing! If I go out and mash the throttle to the floor it will accelerate like normal,until it starts the running out of gas thing,and will stay in a "sputtering" state as long as I hold the pedal to the floor (NO power,just barely staying running all the while). Just for experimental purposes,I held it in this state for approx. 15-20 seconds,it got no worse or no better,just barely ran. I've noticed no odd tank pressure at the cap,the filter at the carb is the correct type and isn't clogged. It's not mounted entirely horizontal,but it's more like at about a 25-30 degree upward angle with the return line in the upward position. The carb was rebuilt about a year ago by the PO,and it runs exceptionally well under all conditions,so I'm not convinced it's the culprit,although I haven't ruled it out yet. Can anyone show me the light? Please? Thanks in advance!

P.S.-Someone mentioned to me that the fuel tank's line could be collapsed at the top of the tank from being over 20 years old, Anyone experience this before? How about what's inside the tank? Plugged screen or something? I really don't know all that much about fuel tanks and what all the correct terminology is for them. HELP!!

Has the jeep set for awhile?
If so it might have rust in the tank, just a thought.
The carb isn't to big for the engine is it?
I had a 73 ford 360 and put a holley 650 on
it, the engine responded like yours so I put a smaller Carter
carb on it and solved the problem

I don't think you've got too much of a carb. Lots of guys have the "sock" problem inside the gas tank. There is a screen by the outlet that gets clogged over time. I'm not sure what else to tell you on this one.

Do you have a fuel pressure tester?? If so put a T in the line before it gets to the pump and see if the problem starts at the tank.

LRRH is right there is a sock type filter in the tank that is well know in the AMC comunity to cause the same problem so i'd start there.

1st, Release the gas cap and see if the problem goes away.
2nd, check the tank, I know, PIA, my 69 was rusting on the inside and the fram filter that was in front of the carb would turn brown from the rust.
3rd, could be the float is stuck so that it does not keep the input open, flooded float will allow constant fuel in and the carb will start acting like a lawn sprinkler. Could be time for a sat afternoon rebuild I just had to to my sons YJ.