EFI with factory Fuel Tank??

[stevencvn72]

So this is my first post on the first forum I've ever found worth reading. I've already learned vast amounts and enjoy the "build" threads emencly. Here's my question. New project is a '67 step, 305 ('85 IROC Z I suspect) EFI with a 700R4. The previous owner routed pick up and return lines and tapped into the factory fuel tank along the bottom corners using JB weld and parts from the local hardware store. Is there a reason that the origional pick up line couldn't be used? Are these EFI pumps too weak to draw the fuel up the line? As unorthadox as it may be I like the tank behind the seat. I have since ripped out the old tank (due to leaks around the previously stated JB weld and hardware) and have a new one poised for the next move. Does anyone have any expirence with this matter? Forgive me if this is elementry or if I've posted this thing incorrectly. Forums are new to me...just like EFI.