Pull the bed or drop the tank is the only way to get to the fuel pickup assy. And the metal lines on it are probably rusted badly, so becareful.

 

Experience question

well i have a wooden flat bed that sits nearly even with the tank so the lines are completely visible. But would i just have to replace the pickup lines? they are incredibly rusty and so are the bolts that hold it down.. im almost positive it doesnt run because of the lines and its just sucking in air. as it started when i poured gas in the carb but quickly died. otherwise it has a replaced carb and fuel pump.

 

... But would i just have to replace the pickup lines? they are incredibly rusty and so are the bolts that hold it down.. im almost positive it doesnt run because of the lines and its just sucking in air. as it started when i poured gas in the carb but quickly died. otherwise it has a replaced carb and fuel pump.

That assembly rusting out is a common problem, been there done that.
It is a complete assembly, like $80 or so from the dealer. The screws that hold it in are like 3mm Philips head, and the head will strip-out right away if there's the least bit of rust holding them in. A pair of vice-grips clamped on the screwhead worked fine for me.

 

www.rockauto.com
They have new tanks too. If it is all that rusty, might just be best to replace it all. This is a very common problem on early Mustangs. The solution always ends up with replacement.